It's a fairly simple job really, i did one on my MR2 a few weeks back.
Wheel, disc, brakes off to get to the hub, hammer out the old stud (or drill it if you need to)
New stud in the hole, it needs to be pulled in so it sits flush with the back of the hub, don't hammer it! I used an old wheel bolt and some washers (so i could tighten the nut without running out of thread) to pull the stud through while using two spanners - one to tighten the nut, the other to stop the hub moving while tightening it.
Once the bolt is through, take the bolt off and put brakes, disc and wheel back on
Hope that helps