Where do I start?

I'm new to the whole opk deal and trying to get to know when I'm ovulating and exactly when to "start trying ". We have been winging it for about 6 years now and mother nature hasn't taken her course,so we've decided to try a few things before going to the doctor. We went to cvs to grab some vitamins that I've seen on an earlier post as well as a specimen testing kit to see if it isn't the boys having difficulties. Getting serious about ttc is a little nerve wrecking but we're trying to maintain our cool. If you ladies have any suggestions I would greatly appreciate it. My cycle is about 40 days, according to the directions it said to start testing 3 days after my period, I saw a faint line tonight (which again the pamphlet said that's a no) here's to hoping we get on the right track!