As said, a 4mm allen wrench removes the filter retainer, then the filter and spring pop out and you'll see a 6 mm allen fitting; use an allen wrench or socket to remove that. You'll probably need to put the reg in a vice, but maybe not. It should be torqued to about 23ft/lbs. When you put the yoke fitting in, don't forget the o-ring in the retainer, and you'll need a modified or special 1" socket to tighten the yoke retainer, use a torque wrench to about 23ft/lbs. Its not difficult. If you're really stuck with no modified socket, you can use a big adjustable wrench or even the jaws of the vice to tighten the yoke retainer. The problem with this is that you will not be able to torque it accurately. With the big wrench, you can try your best to estimate. It's not a super critical torque spec, but its far better to have the torque wrench. You really don't want it coming loose, and I've seen a few yoke retainers really mangled from over-torgueing.