How do you set the points on a 350 Chevy?

Chev 350's haven't used points for a long time. If you have an older one, just put the new points in place & reassemble the distributor, then, with the engine running, open the little window and use an Allen wrench to adjust the dwell. Of course, that means that you will need a dwell/tach.

Newer Chev 350's don't have points.

Correct dwell would be 30 degrees.