The following is by far the easiest headset bearing installation procedure:

1. Drive out old headset cups and crown race and discard.
2. Purchase proper size cartridge bearing headset.
3. Install new headset cups and crown race.
4. Install bearing cartridges oriented correctly.
5. Install top race cap and locknut.
6. Adjust headset and tighten locknut.
7. Come back in 5 to 10 years and repeat.