In order to do this correctly you will need a barrel vise and a barrel wrench as well. As far as the threads it should be the same as any other gun right for tight left for loose. As far as anything holding it in place if you have the gun apart like you should there should be nothing holding the barrel except the threads.

You need a fixture (to go in your vise) to hold the receiver to keep from twisting it and damaging it and a special barrel wrench to unscrew the barrel. I'd take it to a gunsmith.