Welcome!
OPK's aren't nearly as daunting as they seem. On the plus side, if you're ever in question about whether or not they're positive, post a pic here and you'll get a million replies! (We love us some pee sticks

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I'd reccomend "Taking Charge of Your Fertility" if you want to learn about charting. With irregular cycles, charting can really give you a ton of information about your cycles and potential issues. Fertility Friend (website) also has some good tutorials and a charting app for you to keep track of everything.
As for the OPK's, like PP said, you should definitely use them at least once a day. With irregular cycles, I'd take the length of your shortest cycle and go back 16-18 days and start testing then. (For example, if your shortest cycle is 24 days, you should start testing at CD6 or CD8. Whichever you feel comfortable with.) Don't use FMU, and don't drink extra/less than you normally would. Just "go with the flow" if you will...
Your RE will likely want to run a few tests because of your cycles. Definitely a good idea so that you can nip any issues in the bud and not waste time/energy/sanity on trying to figure out what's going on!
Also, I see that you're in Ontario! I'm in Whitby (Just outside of Toronto) so it's nice to see somebody else from around here!