first, you have to make sure you've signed up to be an Amazon affiliate. after you have done this, you will receive a code.
In edit mode, you click on the amazon capsule and open it up to place your products. you can either choose each item yourself by going to amazon.com and clicking on an item and copying and pasting the URL into the box. OR you can let amazon choose products based on keywords and tags in your text. hope this helps.