Dragging. Grab a card, put it anywhere. If you drop it more than halfway onto another card, the app spirals it out to the nearest clear spot by itself, so cards never end up stacked.
Resizing. The bottom-right corner. Minimum 60 px. A new card arrives 300 px wide, so the board keeps one consistent scale.
Panning. Drag empty canvas. Pinch works on a trackpad.
Zoom. A small bar: +, the percentage, −, fit, reset. Range 5 %–250 %, steps of ×1.2. fit frames the whole board in the window; reset goes to exactly 100 %.
Every board remembers its own view. Pan and zoom are stored per board, so switching boards returns you where you were.
Selecting several. Drag a rubber band across empty canvas, or Shift-click. A bar appears: N selected, Move to ▾, Clear. Drag one and the whole set moves. Esc clears, Delete/Backspace deletes.
Arrange
▦ Arrange re-lays the whole board.
What it actually does: cards are packed left to right, wrapping to a new row once the row would exceed 1600 units, with a 24-unit gap, and each row's height is set by its own tallest card. It never resizes anything: a manual resize is a deliberate act by the user, and the code respects that.
The consequence: these are rows, not a grid. The right edge comes out ragged and rows differ in height.
Undo (⌘Z), and what it does not cover
⌘Z only undoes text notes and drawings. The undo stack holds shapes, not card positions. Moving a card is not undoable; you move it back by hand. The stack holds 60 steps.
Something here wrong, or something missing? Tell us — the manual is corrected against the app, not the other way round.