The Edit screen highlights each curve (using the prev curve/next curve toolbar buttons) and lets you drag them around or delete them.

When a curve is selected, a two finger touch and pan from top to bottom smooths the curve.

Navigation beween frames is the same as for the Capture screen. You can use the arrow buttons in the top corners (where appropriate) or a two-fingered horizontal swipe to move between screens.

A plus sign appears in the top right corner (instead of an arrow) when the active frame is the last one.