When to start using ovulation sticks?

Je

I had a chemical pregnancy this month (started bleeding today) and I'm planning to use opk's as I know that ovulation has been a bit all over the place (I had a mc at 10.5 weeks 2 months ago)

If I started bleeding today, when should I start testing? Once I stop bleeding? Is there a certain cycle day you start at?

Thanks guys❤️