How to become an affiliate? step by step?

Hi,
I`m doing marketing for a while, work for a own gaming company.
I would like to get started promoting products for others but have no clue how to get started.
I`m doing pretty good right now but would like to learn how to be an affiliate.
How does it work?
I tried to sign up for Clickbank but they did not accept me ( god knows why )
I`m tying to understand how to use Jvzoo - still struggling
Tried Admitad and they ask for a website , I don`t have one for bringing clients, what should I do?
How do I choose the right product? how do I market it? Do I build my own website?
Is there is any company that provides you template for websites?
How do I do it on FB? make new account and just start marketing the product I want to sell with pixel? Do I have to track it or someone else?
How do I do it on Google? make new account and just make campaigns for someone else?
All this is new for me and I would like to understand clearly how it works.
Some guides or help will be nice!