Trust your doctor - he or she will tell you everything you need to know and get you set up on the dosage that's right for you. That being said, a typical starting dose is around 2mg buprenorphine/.5mg naloxone, but yours may vary. Your doctor will let you know ASAP.
I think 2 or 4mg is a pretty standard dose to start with, but I could be wrong. Your doctor should tell you when you go to start treatment, and then you can know what to expect moving forward. Best wishes to you moving forward - you've got this!