It's easy! After you've registered as an Affiliate, you'll place code in the pages of your web site to display text or banner links (it's your choice!) to Booksamillion.com. The links will contain an account code unique to you to ensure that you get credit for sales that are generated by your site. When a visitor clicks a link and makes a purchase on our site, Commission Junction tracks your code and calculates your commission.
I understand that you said at the end that these keywords would be too competitive for you to go after. But earlier you state, “You can also see on the adwords tool that this has high advertiser competition – this is a GOOD thing for you. This lets you know lots of people are buying ads for this term – more competition usually means more money for you.”
Don’t just hope and pray that visitors will buy; setup everything correctly and make it happen! If you think that visitors will click on your affiliate links and buy just because you placed dozens of affiliate links on your website then you are wrong! You need to have a structured plan in place. Affiliate marketing is a business so you will have a much better chance of succeeding if you treat it like one.