install tar

Hi All out there
I am slowly getting the hang on Ubuntu and I love it.
But tar files are confusing me.

I need help installing then this is the file I have on the desk top.
MyTheme.tar.gz

I have tried to install it
I put in Terminal
cd Desktop
then
 Desktop$ tar -zxvf '/home/goof/Desktop/MyTheme.tar.gz'
it wrote a lot of stuff i guess the program?
now what do I do? Did I get it right?
how do I stall the program from here it made some folders on the desk top

Or is there a better way to do it?
please this is the biggest problem I am having is installing bz, gz etc

Regards Neil