Ovulation test!

So me and my fiance have been ttc for a lil while now we have had unprotected sex going on two years but before i did have an iud and i have a 3 year old with someone from before ive had some health issues and have been in and out the doctor getting them taken care of! Now my fiance and i are seriously stressed and couldnt be more ready to start our family and go through the experience together! I know i need to quit stressing but seriously how can i it gets to the point to where my man feels i just cant conceieve and its just breaking my heart bc he wants a child so badly I decided to really get deep into trying i downloaded glow to help and ive bought pregnancy test and ovulation test i dont really understand when to know when to take the ovulation test though? My periods havent really been regular since i got my mirena removed so do i just start taking them or wait till after af decides to come which was supposed to be on the 11 but im still patiently waiting on her to come any tips for becoming pregnant would be appreciated and also if anyone could explain to me the best time to take the ovulation test itwould  be greatly appreciated! And good luck to all ttc i know if you feel like me then your beyond stressed!! Lol. Just want to catch our break and see a big positive!!!!! Help!!!!