Glow flow

So I just joined Glow about 2 weeks ago. I put in my period for July and it set dates for my aug period which was spot on and just ended yesterday. Does this mean my fertile window is most likely spot on too? 
Which day is the actual day of ovulation, is it the day with the highest percentage to conceive? My husband and I haven't been trying but haven't been preventing either, and then I got this app to track my period and now that I know when I might be fertile I'm feeling tempted to actually try for #3 lol