Go to a command line. Go to the directory where you downloaded gtk+-2-2-2.tar.gz. As root, type the following:
tar xvzf gtk+-2-2-2.tar.gz
This will unpack it. Use SHIFT+PgUp if it scrolls too far down so you can view where it was unpacked to. It is usually unpacked within the directory you are in. For instance, if you are in /home/dubsty13 and you unpack the tarball, it most likely will install it to /home/dubsty13/gtk+2-2-2. Go to that directory with the "cd" command. Once there, type
ls to see the list of contents of the unpacked package. View any and all READMEs, HOWTOs, INSTALLs or whatever other text files to make sure you have all info before starting the install. Once you've done that, type the following as root:
./configure
Once that's done and you get to a command prompt, type the following:
make
This will take a while, but once you get to another bash prompt, type the following:
make install
This will be the last step and you should have it installed at this point. When you get to another bash prompt, it is done installing. Hope this helps