Ovulation test for dummies lol

Jessica • I`m 24 ill be 25 on November 17th I`m married with a soon to be 3 yr old it took us 3-4 yrs to have our son and we want to hsve another baby soon.
I so don't get these tests at all when do u take them?? Do I just go by glow?? I know many of u may think I'm stupid but I've never done any of this. Is taken ur temp very important? ?? A normal Thermometer ok???