birth control tips?

I am starting to get sexually active so I decided to get on birth control. It will be my first time taking these pills. I just picked up my prescription yesterday. Should I take it after my period or should I take it now. I start my period in 9 days. We might want to have sex this week so idk if I should start my birth control now or just wait and start having it after my period and once I’m on the pill. Also, when I take it does it protect me from pregnancy immediately or does it take a few days for it to kick in. We use protection(condoms) when having sex but I also want to have a back up method as well just in case.