Assign FCP functions to a key via the Button List
When the Button List is active if you press a key on the keyboard Final Cut pro will automatically assign the function highlighted in the Button List to that key. To bring up the Button List use option + J, or access it from the Tools Menu. If a function is already assigned to the chosen key, Final Cut will tell you what function is already assigned to the key and ask if you would like to re-assign it. This is a quicker workflow than Customizing the Keyboard, but you need to know what is available.
