Welcome mummyspunkrat!

I have also used the Fortel brand of OPK and also cheaper ones that I have found on the internet. I have found them to be helpful.

I just followed the instructions in the pack. You may find that the test line starts of light (negative) as it gets darker over a couple days, to achieve a positive, I just make sure that I have started BD from the lighter line, as I have found that it is a good indication that I will get a postive soon. I do it just in case.

Good luck and I hope the the work for you.