Leon, by clicking this link, you'll be redirected to the Rules Page on that vehicle. If you look at that row of little colored squares, and drag your mouse on top of one, you'll find the name of that terrain. You CANNOT use am Amphibian Hoverboat on any of those.
EDIT: Just realized you may've meant something else. Assuming you mean how do you pilot it, enter into it and move around (assuming there's more than one room) until you find one that kinda-sorta resembles a sideways head. Then, under the 'Control' sidemenu, the option 'Enter Cockpit' appears. Click that, and the 'Travel' on the little horizontal navigation bar that comes up, just below your vehicle information.