Press (and hold if it's pointing directly in any of the cardinal directions--north, east, south or west--or "secondary" directions--northwest, northeast, southwest or southeast) the SPACEBAR to point the compass in the direction you want to go. Click and hold once the power gets to (one notch lower than) the level you want. (The icon gets larger with increased altitude, so don't use power over about 15 unless you want to completely glitch out the map icon.) Read the first comment if you want to know how to use power 1.
The catapult is implied (couldn't figure out where to fit it in). One "hour" on this planet equals roughly three and a half minutes, therefore one "day" is slightly over an hour Earth time. You may notice, if your character hits the ocean surface, it may immediately head in the direction of the Antimeridian (the west and east edges of the map)--even if there's a closer landmass in the opposite direction. That's because I programmed it to swim in a direction that will always put it on land--away from the Prime Meridian.