ovulation question

My husband and I are TTC our first child! This is a silly question but my periods are irregular at the present time because in September I had a small cyst on ovary but started late as well as last month! But how do I know when I'm ovulating?? I see we're everyone is posting 4DPO or 8DPO and having symptoms  I am trying to know when I'm ovulating? Is it best to have sex every day or every other or does it matter??