Right click on the canvas to open the FSM Context Menu:
There are 3 ways to add states to an FSM:
Add New State
Adds a new empty state to the FSM.
Pastes the Template selected in the Templates Browser into the FSM.
NOTE: You must have a template selected for this option to be enabled.
Pastes previously copied states into the FSM.
NOTE: You must have previously copied states for this option to be enabled.