The editor has three zones: a content sidebar on the left, the canvas in the middle, and a settings sidebar on the right. Everything else follows from one rule: select something, and the right sidebar shows its settings.
The left sidebar is your project's structure:
The canvas shows the current pane at design size. Click to select a block or element, drag to move, drag the edges to resize, double-click text to edit it in place (or press F2).
Whatever is selected - the project, a pane, a block, or an element - its settings appear on the right. If you cannot find a control, you most likely have the wrong thing selected. Press ESC to deselect and step back up to the pane.
When a block is selected, a toolbar appears with the add-element buttons: "Add Text", "Add Image", "Add Video", "Add Shape", "Add 3D Model", "Add Chart", "Add Custom Code", and "Add Background Image" / "Add Background Video".
Your project saves automatically as you edit - there is no save button.
Both sidebars can be toggled: CTRLB for the content sidebar, CTRLE for the settings sidebar. Press ? anytime to open the full shortcuts reference.