Opk advice. Help and questions

So I recently got the strips. I’ve read the directions I know how to actually take them. But I’ve seen people test twice a day. So I have questions.

1- how many times a day do I test

2-is there better times during the day to test

3-if I’m irregular when do I start testing

Ive been trying ttc for a while I just recently started prenatals and this is my first month using opks any advice would be super lovely.

Back story (I started my period the 10th ended the 15th)