Tf2 item display help

[Christopher SteamTrades]

I'v been working on a website for ages now and i cannot figure out how to get a users Tf2 backpack to be displayed on the screen! To break down what i have, i have the basic website, nothing fancy. Then i have a tab directing to my about.php page. On that about.php page i want to display a users TF2 backpack. On the main page of the website you have to login through steam, and all that works fine but i'm lost on how to display a users backpack when they click on the about.php page. I'm somewhat new to php, but i'm really at a loss here. So to break it down, what i want is when a user signs into the website, they can then click on the about.php page and have their backpack displayed. The pictures at the bottom is my current website layout. Is it possible for somebody to help me out here? I'm already friends on steam with you koraktor, so hopefully you can message me on there as well. Thank you for reading, you can email me at chrisste...@gmail.com if you wish as well.

http://imgur.com/I4zklss