Clean the inside of the steering tube, making sure there’s no rust, paint or burrs where the races sit, then use the appropriate tool to drive them into place, bearing in mind, (no pun intended), that the driver should only contact the lip of the race. Lather the races with grease, then pack the upper bearing, and install the stem and adjusting nut. Snug down the adjusting nut to seat the bearings (the operative word here being snug). There’s no need to get carried away with a six-foot breaker bar, just run the nut down until it bottoms and it give maybe half a turn extra to seat everything, then back it off and follow the normal adjusting procedure. From there it’s a straight reassembly job, though as with anything of this nature, I’d caution you to properly torque all the fasteners, and make sure everything goes back where it’s supposed to. Don’t forget; as straightforward as this job is, you’re still performing a fair amount of surgery, so it s easy to overlook a small detail, like properly tightening a caliper bolt or axle nut.