If you applied and were approved by amazon as an amazon associate, then you can put amazon ads on your hubs.
Hubpages recently changed some rules concerning this, you are only allowed to place a certain number of amazon ads per word count, or text. There is a ratio, in other words. More text=more amazon.com ads allowed.
When you click "edit" for any hub, then at the top right of your hub's page are all of the capsules, click an amazon capsule, and place it anywhere you want - so long as it is not the first capsule on the hub. Now you want to click "edit" on that amazon capsule, and then the easy thing to do is click "choose keywords." by doing that you can enter some keywords, like "books," or "electronics," or even more specific things, like "books about electronics," So Forth and so on, then after you have chosen keywords you are ready to "preview amazon results" to see if those are the ads that you want, if not, then you can search some more for the ads that you do want.
Select the number of amazon ads you want, and click "save" and then "done editing," or "publish" at the top of your Hub.
I don't really do so well with amazon ads, at least I haven't done well with them yet. I do better with Adsense or the new Hubpages ad program.