How many days post AF do you Start testing for ovulation? And how many times?

[TTCPLEASE]

So first month using opk.. what days does everyone start testing after their AF? Just conscious I don't want to waste them and do you test day and night? Or if its not positive in the day do you take that as a no? Thanks in advance 😁

Evening test done.. it doesn't even pick it up as anything on the app ive lined it up it just says 0 no reading i think its darker than this morning.. I dont think premom likes me very much 🙈🙈