For quick reference, you can access the cheat sheets for each keyboard layout. There are two versions of each cheat sheet, a basic one with only the most important commands —very useful if you're starting with Vem—, and a full one with the complete list:
Vem's commands are distributed spatially across the keyboard, which means that command positions change depending on the keyboard layout that you use. Vem supports the QWERTY, QWERTZ and AZERTY layouts. By default, QWERTY is used. If you have a different layout, configure it by following the instructions at the Keyboard layout section of the documentation.