Walk up to the captain standing outside the tent. He will brief you more before meeting the wrong end of a sniper rifle. Now head into the tent and pick up some more ammo and any health/armor you need. After that you should move to the other side of the camp (away from the helicopter and over the flipped over truck) and into the jungle. Kill the 5 people waiting for you around the corners and proceed forward to exit (you will pick up a shotgun and an AK47).
