Using OPKs... how often?

Sarah • ❤️ one Heavenly baby 9/14/17 👶🏼 rainbow baby Luke born 9/12/18 🌈 angel baby Max born sleeping 8/10/20 👼🏼

I just used OPKs for the first time this month. Unfortunately, AF showed today so I’m trying to be optimistic and plan for next month.

Despite ovulating later than most (CD19- CD21), Glow still shows my fertile days to be earlier in my cycle. When should I start using OPKs and how many times do y’all test each day?