To work with affiliating means that you can resell someones product and make a profit from that. You may first have to buy the product - for example a digital product - that is exposed on the net. When you have bought the original product - then you can become an affiliate eg. reseller of the product.
You will get a special link to the digital product so that you will be able to get paid when someone is buying your product as the special link you will get is unique for YOU. When you promote your special affiliate-link - your costumers will be able to buy the product from YOU - meaning you are actually helping the original product-producer to get his product sold. You will, therefore, earn a commission every time you are able to resell the product as a "thank you" from the product producer.
You can also become an affiliate of an online store in order to resell that stores physical products - like ceramics-articles, clothes, books or whatever that store is offering you to buy. I have added some physical store here on this site so that you can become an affiliate on those articles.