Newbie to OPKs

RM 💕

So I used OPKs last cycle but I started using them fairly late (I think). AF arrived yesterday for me so I was wondering when is the best time to start using OPKs???

Last cycle I did catch my surge on CD#16 for me. But I know sometimes you can ovulate later or sooner.

Any advice or tips would be greatly appreciated 👏🏻🤘🏻