How do I get past bridge over river Kwai?

If this is the tree on the hill after you blew up the tank with that grenade launcher thing, then I had the same problem. The trick is, when it said go to the right, it meant if you were facing the top of the hill. Go to the other side of the hill and look for an opening. That's where you want to go. To go through the tree on the other side of the hill, you would need the machete, but I don't know how to get that.