Depends on what's around me. But I'd start out by talking to myself. That's how it always starts. Observe your surroundings, make sure there is food around, clean water is available. Then focus on a place to stay, safety. After that, fishing for fun. Making a little boat would be entertaining, nothing big, just to go around the area. But as a hobby there? I would probably play with my hair, gather shells, improve the place, carve a pipe and flute, etc. There is always plenty to do, no matter where you are.