Preview and Test a Lesson
Check scene flow, grading, media, variables, and learner interactions before assigning a lesson.
Preview is where you experience the lesson as a learner.
Use it before assigning anything that includes branching, grading, media, variables, timers, or hidden feedback.
Starting preview
The Preview button lives at the top of the Studio. In the editor it previews the scene you're currently on — the chevron beside it opens Preview from Opening Scene, for when you want to walk the lesson the way a student actually starts it rather than jump straight to the part you're building. From the Lesson Graph, there's no "current scene" to fall back to, so Preview always starts from the opening scene there.
You don't have to open the Studio first. On the Lessons page, each lesson card has a Preview button (the play icon beside Assign), and the ⋯ menu on every lesson has Preview too. On a lesson's own page, Preview sits next to Edit Lesson. Each one opens the lesson straight into Preview from the opening scene; when you leave Preview you're in the editor, ready to fix whatever you spotted.
What preview looks like
Preview opens on the lesson and nothing else, under a single line that says This is what your students see. The lesson is the whole screen, because the lesson is the answer to the question you came here to ask.
The two instrument panels are still there, tucked into a labelled strip on each edge:
- Scenes on the left — the scene list, for jumping straight to the part you want to test
- Debug tools on the right — the Event Log, Conditions, Variables, and Scoring views
Click either strip to slide the panel open, and the arrow in its header to tuck it away again. Berdee remembers which ones you had open and brings them back that way next time, so if you live in the Event Log you open it once and it is there from then on.
Restart the attempt
Restart sits at the top right of the lesson, next to that line of framing. It replays from the scene you started this preview session on and wipes the attempt completely clean:
- Scores go back to zero
- Variables return to their starting values
- Every scene is un-visited again, so first-visit behavior fires properly
- The Event Log is cleared, so the rows you are reading belong to the run you are watching
That last one matters more than it sounds. Testing a wrong-answer path and then a right-answer path in the same session leaves you reading two runs' worth of events mixed together; Restart between them gives you a clean log for each.
Restart always returns to the scene the preview session began on, not whichever scene you happen to be on — so if you opened preview on scene 4 to test one activity, Restart puts you back at scene 4 rather than at the top of the lesson.
What to test first
Start with the basic learner path.
Check that:
- The opening scene is the right first scene
- Every Continue or Next button goes where you expect
- Learners can tell what to do on each scene
- The lesson has a clear ending
- No scene feels crowded or confusing
If the main path is unclear, fix that before testing advanced logic.
Test interactions
Any widget with an interaction should be tested directly.
Check that:
- Reveal buttons show the right content
- Submit buttons check the right scope
- Retry buttons reset the right answers
- Media buttons play or pause the intended clip
- Drag-and-drop targets accept the right items
- Timer completion triggers the expected action
For classroom use, one reliable interaction is better than several clever ones that are hard to predict.
Use the preview debugger
Open the Debug tools strip on the right when you need to inspect logic instead of only clicking through the lesson.
The Scenes strip on the left mirrors the Scenes panel you edit in — same thumbnails, same order — so you can jump straight to the scene you want to test instead of clicking through to reach it.
The Event Log on the right is a running play-by-play of what the lesson just did, newest first: Continue was pressed, Set score to 3, Moved from Warm up to Question 1, Multiple Choice 1 answered incorrectly — 0 of 1 point. Click any line to expand it for the details behind it. Use the filter chips to narrow to Interactions, Actions, Scenes, Values, Show & hide, or Scoring.
The log is the fastest way to answer "why didn't that button do anything?". A line like Launch was pressed, but its condition was not met tells you the press registered and the condition blocked it; Launch was pressed, but nothing is set up to happen tells you no interaction is wired to that button at all. _Example: Find out why a button won't work in Preview follows a Check button that says "Not quite" to a right answer, from the Event Log to the Conditions and Scoring views, and fixes it._
The Conditions view lists every interaction on the current scene that has a condition attached, with a live pass/fail indicator for each one. Press buttons and change values in the preview and the indicators update in real time — handy for working out why a gated button refuses to fire. The Variables view shows the current value of every variable in scope and updates live as the lesson changes them, and the Scoring view breaks down scene and lesson totals widget by widget.
To see or _change_ the map of scene paths, use The Lesson Graph — the editable diagram of how learners move through the lesson.
Publish validation still blocks structural problems such as duplicate widget IDs, duplicate widget names on the same scene, more than one Submit button on a scene, and a lesson with no Submit button set to Lesson. Problems with the lesson's ending and its flow — a scene with no way forward, an unreachable ending, an ending that leads back into the lesson or still grades — come through as warnings; see The Lesson Graph.
When the publishing checks start appearing
A brand-new lesson already has an opening scene and a closing scene in it, and neither is wired up yet — so on day one those checks would greet you with a list of problems about a lesson you have not written. They do not.
The publishing checks stay quiet until one of two things happens:
- You add your first widget — anywhere in the lesson, on a scene or a layout. From then on the badge in the top bar and the issue dots on the scene cards behave exactly as they always have.
- You open publishing — at which point the list is the direct answer to what you just asked, so it appears whether or not you have started.
Nothing about what Berdee checks or what it blocks has changed. This is only about when it speaks up.
Preview never records an attempt. Walk all the way to the ending and the completion bar says Preview only. Nothing was saved. — no gradebook row, no locked answers, nothing for a student to inherit. Preview the lesson as often as you like.
Test grading and scoring
If a scene is graded, test both correct and incorrect paths.
Check that:
- Graded widgets have the right correct answers
- The point values feel reasonable
- Scene score includes only the widgets that should count
- Lesson score includes only the work that should count across scenes
- Custom grading groups are submitted by the correct button
- Pass and fail navigation go to the right scenes
A useful habit is to intentionally fail the activity once, then pass it once.
Test variables and personalization
Variables are easy to miss because they work across several parts of a lesson.
Check that:
- Variables start with the expected default values
- Buttons and interactions update the right variable
- Conditional visibility changes when the variable changes
- Liquid template text shows the value you expect
- Variables hold the values you expect as the learner moves through the lesson
If personalized text looks blank or unchanged, confirm that the variable exists and is being set before the text appears.
Test media
Media problems are easiest to catch in preview.
Check that:
- Images load and are cropped the way you expect
- Audio can be played before the learner needs it
- Only intended audio plays automatically
- Video controls match the activity
- Generated sound effects are not too loud or distracting
- Text-to-speech reads the right text
For listening tasks, test with the volume low and with the volume normal. This catches audio that is either too subtle or too disruptive.
Test layouts
If a scene uses a layout, check both the layout and the scene itself.
Check that:
- Shared navigation appears where it should
- Repeated score or timer widgets stay visible
- Scene content is not hidden behind the layout's content
- Scene-specific widgets still feel like the focus
If every scene using the same layout shares the same problem, the fix belongs on the layout — one edit reaches them all.
Quick pre-assignment checklist
Before assigning, run through this list:
- Start from the opening scene.
- Complete the lesson once as a successful learner.
- Complete the lesson once with at least one wrong answer.
- Test every button that changes scenes.
- Test every media widget.
- Check that scores and feedback match the learner's work.
- Review any hidden hints, explanations, or retry paths.