Nancy,  I'm in SW Colorado.  You can actually order them through the state here, but you may want to check with your county first.  To place them, you lift a patch of bindweed and put them under it, then press on it.  Then don't disturb that area for that season.  Eventually I hope to be able to let the county here harvest them from me.  They cut out a patch of bindweed and bag them in paper.