Brave 4 Pro action camera does not have a mode button on the camera body, and therefore it is not possible to switch between different modes by pressing a button in the waterproof case.
To switch between modes on the Brave 4 Pro, you will need to use the touchscreen interface.
There are 6 modes: Video, Photo, Burst Photo, Time Lapse Video, Timer Photo, and Wifi. When the camera is on, tap the current mode at the bottom of the camera screen or swipe up to enter the mode menu.