Step 1: Find affiliate products
Find a product to promote that has a good commission for each sale. Generally you will receive the higher commissions in Clickbank, Commission Junk, Amazon, eBay, etc.. But what I recommend you is to focus in digital products.
Step 2: Buy a Domain Name
Get a good domain name to redirect your visitor to your affiliate link. A domain name is .com name in order to identify your name on the web.
Step 3: Attract Visitors
With the approach of getting sales, what we need is get the most quantity and quality of visitors to your website in order to they buy your affiliate product (your domain name will redirect to the visitors to your affiliate link that you are already promote)