How do you properly do the opks

Jessica • I have one healthy beautiful two year old son. Now hubby and I are going to try for another baby! 👶🏼
I am starting opk in August after my AF comes. I just got off the Nuvaring and want to make sure I am ovulating and start my BDing! Is anyone willing to share photos of what to expect? The negatives to the positives? Maybe a timeline? Tips?