When should I start using opks?

Sarah • Married, 24, mom of 2💗💙

Just received them in the mail today! 😊

My periods are regular but last month threw me off because I didn't have a period in july.

I started my period August 17th.

Should I start using them tomorrow?

Also please give me some advice/ tips as it's my first time using opks!

Baby dust to all!!✨✨✨