OPK question

Erin • Married ❤️ Mommy to Ava Noelle 11/17/17 💜
Ok so I wanna start using OPKs this cycle - this will be our first cycle TTC since our miscarriage last year. I have a 26 day cycle and think I ovulate kinda early- does anyone have any advice on when I should start testing?!! Thanks ladies! 💕