Contraceptive pill

I'm curious as I'm going to go on the birth control pill as to whether anyone knows about it in terms of when you start taking it (eg, the first day of your period or when your period finishes) and how long it takes to get into the body properly for you to have unprotected sex (unless you used a condom) but I've heard that you should definitely use a condom for the first month, is this true? And also I'm going to an appointment to hopefully get put on it I think when my period is meant to start/ already started, so will I have to wait a whole month till I can actually go on it if you have to take it the first day of bleeding? Does anyone know anything about this? Thank you :)