Open a lesson's Build button and you are in the builder. The left rail holds four panels: Insert blocks, the palette, in groups that open one at a time; Layers, the lesson as a tree; the Component library; and the Media library. The canvas in the middle is the lesson as learners will see it. The inspector on the right edits whatever is selected on its Content, Style and Advanced tabs. The top bar carries undo and redo, the Issues list, Preview, the breakpoint switcher, the save state and Publish.