TTC without a cycle

💜𝑺𝒉𝒆𝒍𝒍𝒚💜 • 💙 Boy mama 💙

We are ttc #2 but I am still breastfeeding #1 and have not gotten my cycle back so I am resorting to OPKs. I used them to get pregnant with #1 but I was using them wrong apparently, I was testing with FMU. I have done some more research because I am struggling to conceive #2 and found out you're not supposed to use FMU. What is a good time to test?