Affiliate marketing is a method of promoting web businesses, where advertisers such as merchant who sells their product or services online. In return, the affiliate, who is the owner of the site, that chooses to display a merchant's products and services can earn commissions, on clicks, leads, or purchases that being made through the links on their site.
Affiliates or publisher agree to place advertiser promotions on their web site in the form of graphic or in a text links. This system of Affiliate marketing allows merchants to pay their affiliates based on performance.
So the concept is as simple as this, a customer visit an affiliates program then affiliate/publisher will direct customer the their partner/online merchant's as soon customer purchases on their products then thats the time when affiliates get compensated or can be paid of.