Opk help

A little help please ladies! Last time I was actively TTC I had one of those expensive clear blue easy monitors that reads the strips for you and all that. I passed it on many years ago. I know this is a negative result but I am new to this opk game. On CD 14, OV is predicted for CD 17 via glow app. Is there anyway to tell by the test if my LH is on it’s way? What’s the general time to get a positive opk before OV? Sorry for all the questions. I haven’t TTC in over 7 years. I have just been tracking my cycles with glow and logging any changes and symptoms for the last few months.. But Dh has some issues with ED and sometimes he isn’t home during my fertile time. This time we made his schedule around my fertile week. Fingers crossed for all of us!