If you are using Firefox and you want to set att.net your homepage, select tools in your browser menu and click options. Then, under the general tab, type att.net in the space provided for homepage and click "ok". On the other hand, if you are using Google chrome, click the wrench icon, then click options, basics then select open this page and enter the website.
To make a certain site your home page, you need to go to the options for your browser. Once there, you will find a tab that contains the words "home page" with an entry field next to it. All you have to do is enter the webpage address on it then save. Next is you start your internet browser and it will then go to the site that you entered.