I'm super confused. someone help!

This is our first month officially TTC! I've been taking OPK's the past few months and have tried basal body temperature but still don't understand. 🤔🙄
Soooo someone enlighten me, PLEASE! 
Once you get a positive OPK, should you BD? Or is it best to BD before getting a positive OPK? Or both? When do I ovulate in relation to a positive OPK? Why am I getting a positive OPK for more than 1 day? 
I have a doctors appointment to discuss this more! But I'd love some insight from you ladies who seem to have it figured out :)