How to install T3 template with sample data as its shown in the Demo

I would like to install T3 template with sample data as its shown in the Demo. I tried to install "t3_blank_j33.zip" but it fails every time.
May I know what is the issue. Also how its possible to expand the contents to cover full screen. I see header and footer are touching side of screen but not the body. How this can be achieved.

P.S. I am a beginner and sorry for asking basic help.

Thanks,
Avinash