Stored in the camera is a program called actionplus which allows you to set various functions. PHOTO can be set to single, burst or time lapse and also photo resolution to vga, 3mp, 5mp or 16mp; VIDEO choose FHD resolution of either 1080mp or 960mp and HD res to either 720mp 60 fps or 720mp 30 fps. General settings allow you to select either PAL or NTSC, AUTO POWER OFF select off, 1 min or 3 min; auto-rotation on or off; and setup for date and time.
The Helmet mount has 3M adhesive undeneath and you can stick it onto the helmet top or side of the Helmet.
You can then clip the camera (with CAM lock) into the socket of the helmet mount.
The drawback of this is the helmet mount will be glued to the helmet.
With bike helmet you can just apply the straps through the vents without using the SM adhesive pad.
I think it is too heavy for snorkeling. On my last trip I just tethered it to my watch which made it easy to switch from picture mode to video mode. I also used an Easy Shot Clip HD attached to my mask which worked very well.