Bitpaper is designed to be used with hotkeys for speed.
A few of the most important shortcuts are:
Z and X are undo and redo, respectively.
The numbers 1 - 9 change the tool selected.
< and > move the pages back and forward.
Ctrl/Cmd + C and Ctrl/Cmd + V are copy and paste.
A full list can be found by pressing K and any time.