From Alpha spawn, stay on the bottom floor and walk out to the double doors. Once you get out, look to the right and there will be a fence. To get over it, follow the fence to the palm tree at the end and tell a friend to take cover on it. Once he does, tell him to get off and walk to the left a short distance. Here, you should be able to take cover in mid-air. Tell him to look out to his left as far as he can, then have your player go to the side of the palm tree facing the fence. Back up slightly and you should be able to take cover in mid-air also. As your friend looks to his left as far as he can, lean out to your right, into your friend. Then, release everything and walk forward, over your friend's head and directly into the palm tree. Walk into the fence along the top of the fence and move back to the Alpha spawn double doors. When you get to that wall, back up slightly and tell your friend to crouch and take cover on the wall and get as close to the fence as possible. Walk onto his head and tell him to stand up. This should boost you up and over the wall. If you do not get the palm tree glitch the first time, keep trying as it sometimes requires several attempts.