Need advice ladies

Arielle • 20 yrs old married to my best friend who I known with for 6 years we had miscarriage in Jan 13 2016 now trying again (: we delivered our beautiful baby boy March 22 2017

I am getting on the pill I want to know the proper way to

Take it to not get pregnant. I confused about the white pills? Do you take them? What are they? When do you start the new pack