Just purchased my 1st OPK!

Morgan

Trying for baby #4, & just purchased an opk via Amazon. I have never used them in the past but had some issues getting pregnant with baby #3, so figured I’d give these a shot! This will be our final and last baby, so I just want to start my journey a little differently this go round! Any tips? When should I start testing? Just ended my cycle, so I don’t want to start too early nor too late!