at first you need to visist the page of Adblock and download the aplication. Adblock block a lot of publicity, but desnt do it automatically on all the pages. In this cases you should click on the red button on the right upper corner of your browser. You can there manualy choose to block the adds on the site. You will also now notice that as you move your cursor over the webpage the sections with adds will highlight, showing you how AdBlock sees the website.
I hope it helps you something