New to opks!

Doing a trial run this month with opks just so I can understand it better because I don't wanna try again to get a third BFN. i started testing everyday so far since cycle day 10 and for me now its cycle day 13. glow says I'm due to ovulate in a couple days and I can't actually see if the line on my test is getting darker. how many times a day would you recommend testing? is the line showing that I will be ovulating soon? all I know of opks is from what I've seen on here. any help we would be really grateful. Baby dust to all❤