When to start the pill again after being pregnant?

I went to my 6 week appointment yesterday after giving birth in November. I’m still slightly bleeding although I’m not sure if it’s my period or just bloody discharge from the birth. I got my pills today from the pharmacy but I’m not sure when to start taking them. Is it based on your period or just start it on a Sunday since that’s when they start? I have no clue. I was going to wait until Sunday then start but I don’t know if I have to time it to my period somehow or not.