When you awaken, you’ll find yourself in a hut with a man named Dennis. He will be teaching you some basics about survival, as well as give you some cash to buy your first weapon from the general store in town. Go inside the store and buy the 1911 handgun. You can buy the weapons from the stores, or if you activate Radio Towers, you can get them for free.
Once you bought the gun and exit the shop, follow Dennis out of town. On the way, Dennis will talk about the Radio Towers and how you can deactivate the scramblers, which will open up some more of the map, make weapons free in the store and unlock new Supply Drop quests. Before you start heading up, check the buildings around you for some loot (lootable items will flash). These lootable boxes will usually contain money, items you can sell and sometimes ammo.
After looking around a bit, start heading up the path that leads to the Radio Tower. Once you reach the top, a snake will lunge and latch onto your arm, but you throw it off. You can kill it if you want, but it doesn’t really matter. Loot the boxes around and inside the building, then start climbing up the tower. Once you get to the top, deactivate the scrambler, then use the zipline to get back to the ground. Open your map and listen to the instructions, and when you close your map, the next mission will automatically begin.