View

Show background
Solid colour background
Background colour
Lock cover to book
The same background sits behind both the cover and the open book. With “Show background” off you can use a flat colour instead — turn on “Solid colour background” and pick a colour, or leave it off for a transparent PNG. “Lock cover to book” snaps the cover to the interior’s right page so they’re one book.

Preview.

Scene

Cover

Full cover uploaded
Turn on if your file is a wraparound (back + spine + front). Only the front (right half) is used for the mockup and the closed book.
Drag the cover on the stage to move it. Drag the cyan dot to resize.

Placement