The new inner race should be pressed in first, minus bearings. Beating it with a hammer is a sure way to deform it, and it needs to fit TIGHTLY in the hub. Pressing it in is the best way. You could always freeze the race and heat the hub if you don't have access to a press. You'll have to replace the rear seals of course, but that's expected.
Yes, these are a different setup than the twist and cotter pin kind. Torquing them properly (go to the high side, 150 lbs) is the key to their longevity and even though it seems to go against all we know about bearing set up, it is the correct way to do these. If you don't have a tool to fit the locking ring, maybe you can make one ( a couple of guys here did ) or borrow one. Use waterproof grease and pack em good.