Once you’ve got a topic and possibly some products to promote, the next lessons you’ll want to go through are ‘Finding and Registering a Domain Name’ and 'What to Look for in a Hosting Provider.' These will give you a hand with setting up your own domain name and hosting, and then you should have some help from your hosting provider to install WordPress. 
For example, if I talk about how cool a product is, and then you find out that I’m an affiliate for them, wouldn’t you as a conscientious observer become skeptical as to whether my information is biased, if perhaps I’m only saying how cool something is because I can get paid for it? Wouldn’t that make you question my integrity with other things I say as well?