This definition applies for every command/option that can be executed, typing on your keyboard, a key or key combination specified.

Example: a button with the Scan option (please note the underline on the S), can be executed hitting the Alt key on your keyboard, hold it down, and hit the S key on your keyboard at the same time.... then release both keys.

If you found a keyboard combination like Ctrl+C or Ctrl-C, it means you must press the control key Ctrl on your keyboard, hold it down, and press the C key.... then release both keys.