It sort of depends how many seeds you wish to grow. If you want as many as possible allow the plant to bud for three or four weeks. Then bring a flowering male near her and shake him a little on her. Let them mingle for a few days and seeds will start developing.
If you just want a few dozen seeds then keep her budding for 6-8 weeks. Trim off the really ripe buds. Then repeat the pollenating I described above.
Keep large sheet cake pans underneath your plant. Seeds can be picked, but, many will ripen and drop in the pans.