The first section in Interface Settings is Action Hotkeys. This section is where you can set your input method between keyboard and gamepad. You can also rebind keys for movement, combat and Interaction. Simply click on the key you wish to change, and it will swap to input mode. Push the key you want to replace the default with and apply your changes.
The second section in Interface settings is UI Hotkeys. You can change you input method between keyboard and gamepad, and rebind hotkeys specific to menus and chat, in addition to the show/hide cursor button.
The third section in Interface Settings is Quick Slot Hotkeys. You can change your input method between Keyboard and Gamepad, as well as rebind the hotkeys you use to activate quickslots.
The fourth section in Interface Settings is Misc. Hotkeys. You can change your input method between gamepad and keyboard, and change hotkeys related to in game voice chat, as well as camera controls.
The fifth section in Interface Settings is Mouse Interface. You can change the way your mouse behaves, such as inverting its movement, increasing its sensitivity, or even using click to move.
The last section in Interface Settings is Gamepad Interface. You can use this section to enable your gamepad, set its sensitivity, or invert its movement.