Creating Your Site
Get a domain (yoursite.com) and then sign up for a web host and build your pages. I highly recommend using WordPress or blogger to create your site because you just pick a theme and your site is up and running.
Once you have selected your theme, you can add AdSense ads by either using a free AdSense plugin or you can use the WordPress or blogger Text widget to easily add ads to your sidebar.
If you want to learn more about WordPress I have a video here.