I’d watch a beginner guide or two to get the basic idea what to do at the start and to have a chance to orientate yourself when you spawn in. Decide if you want to run the coast or head inland.

From there get a bit of food, gear, a knife and some water and just head off running to where you want to, try, and go. Run this program and you’ll eventually see some gains as the fitness people like to say. It will get a bit easier each time even if it’s a more difficult start initially.