Ovulation tests advice wanted!

So ive never tried an ovulation test before this week ive tried 2 on yesterdsy and one todsy whats the deal with them do people tend to find they work? Are they accuarate do they help you at all? Im just a little confused how it works on the app do you release an egg during the green section of days or before those green days begin? Sorry just only verrryyyy recently even started trying less than a month but tryinh to keep good control of things as i have a medical condition which has to be closely monitored in pregnancy :)