Ovulation Tracking Newbie!!

Looking for help / advice!

I have been TTC for 2 months now. I decided to try tracking my ovulation since my period is now considered irregular. I was on the pill up until January. My period came normal time for Feb and March. Now April I was over a week late, had my hopes up, took 3 tests and all negative, and then got my period. So my period was over a week late and also longer than it normally lasts. I am on day 7 of my cycle. When should I start tracking? I bought an ovulation kit for 10 days. I use 2 different apps that state I am predicted to ovulate 4 days apart. First day is 4/28 and the next is 5/1. Any help / tips / tricks for a first timer for ovulation?! It all seems so overwhelming