Never used ovulation test! Help!

So hubby and I are on month 4 of ttc baby #2, but also found out we have euraplasma so we're taking antibiotics. No one is really educated about it but it's a bacteria passed by sex and while you have it it can make you infertile! So long story short we are getting rid of it this week and I ordered some ovulation test and pre seed for this month! This may sound stupid, but I've never used ovulation test before and was wondering how they work. If it comes positive does that mean you're ovulating right then or can someone just kinda explain the time frames 😭😂