Understanding Ovulation Kit. Please help?

Question

I don't know why, but for some reason I can't quite grasp how an ovulation kit works. Could somebody please explain it to me, and which one should I buy??

Answer

You test your pee (usually from cycle day 10) in the early afternoon. 
The test line needs to be as dark or darker than the test line to indicate positive. 
Positive means you will ovulate in the next day or two so you're at your  peak fertility

Understanding Ovulation Kit. Please help?

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