Canvas, selection and layers

The canvas shows every section exactly as it publishes. You select, move and resize things on it, and the Layers tree shows the same page as an outline.

Moving around

Zoom with the wheel, a trackpad pinch, ⌘+ and ⌘−, or the zoom buttons. Zoom follows the mouse pointer, so the spot you are looking at stays put.
Fit and 100%. ⌘0 fits the page to the screen; ⌘1 shows it at actual size; ⇧2 zooms to the current selection.
Pan by holding Space and dragging, like in Figma, or with the middle mouse button.
Devices. The device switch in the top bar shows the page at desktop, tablet or mobile width. Every style you read or change belongs to the device on screen (see Layout and responsive).

Selecting

Click once to select. Text and headings are selected directly on the first click. Containers select from the outside in: the first click picks the outermost block, each further click goes one level deeper.

Several at once. Shift-click adds or removes an element. Drag from a section's empty space to box-select; Shift-drag box-selects from anywhere.
Clear the selection with Esc.
Breadcrumbs at the bottom of the canvas show where the selection sits; click a crumb to select its parent.

Changing the layout by hand

Padding handles. Drag the pills on the inside edges of a selected element. A badge shows the value as you drag.
Resize handles on corners and edges set width and height. Hold ⌥ (Alt) while dragging to resize without snapping.
Reorder by dragging a selected element towards a sibling: the drop line shows where it lands. Arrow keys nudge 1px, Shift + arrow 10px, ⌘↑ and ⌘↓ move the element earlier or later among its siblings.
Align a multi-selection with ⌥A, ⌥H, ⌥D (left, centre, right) and ⌥W, ⌥V, ⌥S (top, middle, bottom).
Group with ⌘G and ungroup with ⌘⇧G.

Layers

The Layers tab in the left sidebar lists the page body, its sections and every element inside them.

Rename, hide, lock, duplicate and delete from each row.
Drag a row to give an element a new parent, or to reorder whole sections.
An element that is hidden by a Show when rule is revealed on the canvas while it, or something inside it, is selected in Layers, so conditional blocks stay editable.

Right-click an element for copy and paste (inside or beside the target), copy and paste style, duplicate, rename, delete, change a container's HTML tag, convert to or from a repeater, and wrap or group the selection. Copied elements can be pasted on any page of any website you can edit.

Draw tools

The tool rail in the top bar has draw tools for a container, a text box and a rectangle. Pick one, then drag on the canvas to place it at the size you want; Esc cancels.