How to set breaker points?

Perfect. The thing no one asked is why the op was adjusting point gap. May be the engine was built with a big cam and he is trying to smooth the idle out. May be it has a bad plug or a plug wire pulled off. Who knows. I don't think I ever read what the issue was.
He did say it was running badly. Maybe we can at least help him eliminate the points as a source of that. Oh and one thing I forgot to add.....make sure the faces of the points are CLEAN and not burned or pitted all to hell and back. You might even get a small file and file them so that they have a fresh surface area if they need it. If you don't have a point file, an emery board works very well.