The Ultimate Character Controller is an Editor Extension so when you import from the Asset Store it does not bring the project settings with it. After the Ultimate Character Controller is done importing the following dialog will appear:
The next dialogue relates to updating the input button mappings. By default, the Ultimate Character Controller uses Unity’s input system which relies on the Input Manager. The Input Manager requires the button mappings (Jump, Crouch, Fire, etc.) to be created ahead of time so this dialog will add the required button mappings. It will not override a button mapping that already exists.
The next (and last) dialog that will appear relates to updating Unity’s layer settings. This is recommended so the correct default layer names appear. These layers can later be remapped within the character’s Layer Manager.
If you would like to perform the button or layer update later on you can do so by selecting the Tools -> Opsive -> Ultimate Character Controller -> Main Manager menu option, then selecting the Setup button followed by the Project tab.