You need an e-mail list because it will give you an audience to directly market your affiliate offers and products to. Marketing via e-mail has been shown to be much more effective than other forms of online marketing.

The standard method of getting a list goes like this:

1. Create a webpage (called a squeeze page or landing page) where you will offer something to people for free in return for signing up.

2. Set up an automated e-mail service so that people who sign up for the list will automatically receive your free offer. Aweber and Getaresponse seem to be the popular choices, and I've personally found Aweber super-easy to use as a non-techy person.

3. Make sure your offer (usually a downloadable product) is something genuinely useful and original.

4. Drive traffic to your list. There are lots of ways to do this, but for a complete newbie solo ads are the simplest. I've gotten good results from buying solo ads here on Warriorforum. PM me if you'd like to know the service I used.

5. Start marketing to your list. But try to do it in a way that presents yourself as helpful. No one likes pushy marketers.

This is a hugely simplified explanation, naturally, but I hope this explains the basics. I'm new to all of this myself.