Let’s assume you register yourself with an Affiliate Network and decide to promote a product which is, say, a Coffee Maker. You promote it with various means like creating websites, posts on your site, PPC advertising, banners and text ads on social networking sites. Now someone clicks on those affiliate links and buys one or more products. Then that will be called a sale through your affiliate link. Once done successfully you will get the commission as fixed by that merchant.
This should bring you to a landing page. Many companies use an affiliate marketplace like ShareASale, CJ, or Clickbank. These are free to use and you can create a free account.

This post is an introduction to affiliate marketing for bloggers who are looking to monetize their blogs. However, there are other monetization methods also if you want to have a look, after this post, of course.
For example, a person searching for “types of iPhone chargers” may simply be doing some research, and the buyer intent may be only medium at best. Someone conducting a search for “where to buy iPhone chargers online” indicates an extremely high intent to buy the actual products.