Hi and very welcome! You made a very good start by coming here. A lot of us, including myself, were surrounded by a drinking life when we decided to stop. It's not easy, but you can do it. A lot of people on here will provide wonderful support and ideas on how to get through the tough times.
I know I have to quit, but do not know how.
We all know we have to quit, what made it a lot easier for me is 'wanting' to quit. Huge difference in my opinion. Once you want to do something you can deal with outside influences much better.
Keep reading and posting and let us know how you are.