Shortcut keys are shown in the way they are visible on the keyboard. For example:
G This stands for the lower case “g”.
Shift, Ctrl, Alt These are modifier keys.
Ctrl-W, Shift-Alt-A, … This notation means you have to press these keys at the same time.
We use the following schema to reference mouse buttons:
LMB Left mouse button
RMB Right mouse button
MMB Middle mouse button
Wheel Mouse wheel