There are two ways to create blog, first is free means crating free blog at wordpress.com, blogger.com etc. Second is paid means you will have to buy a domain name as well as hosting then use any blogging platform. After this, you will have to publish some unique and useful content on your blog then apply for advertising to make money from blog.
First you need to create blogs on blogspot, wordpress, weebly, tumblr, etc. After creating blog, you will need high quality contents.. Think of interesting blog post for branding. Do SEO. Share your blog on social networking sites. The traffic you make can be turned into money.