Pan: drag an empty area.

Zoom: scroll up and down over the plan.

Move: drag a piece. Hold Alt to move freely, ignoring snapping.

Resize and rotate: use the handles around a selected piece.

Edit: double-click a piece, or use the pencil in the list.

Measure: open the Tools menu, then click two points to read the distance.

Floors:Pro add another floor with the + beside the floor tabs.