The help refers to the action ‘Perform a Finish’ when describing how to use certain commands. In EdgeCAM, selecting the right hand mouse button will finish a command.
Alternatively, selecting the Enter/Return key will also finish the command.
You can also use the Finish command.
In the standard configurations this command is not present in the User Interface, so you will need to add the command button to a toolbar or menu yourself. The command is in the Input Options category.