Go
HERE and
HERE for detailed instructions.
I used the paper clip method. Take a large paper clip, straighten it out and bent each end into a tight "U" using about 1/4" on each end. The "U's" will let you push the clip into the proper pin sockets on the diagnostics connector and hold the clip in place while you switch the ignition on for the appropriate time period.
Depending on your year model, you'll bend the paper clip into a large looping "U" so that you can "jump" the correct pin sockets on the diagnostocs connector.
On my '93 325i it took a few tries to get the service lights to reset to green. I discovered that I had to count the seconds that I left the ignition switch at step 2 carefully. If I left the jumper in and the ignition on too long, the lights didn't reset.
HTH
If you have problems let me know.
Fred