A .tar file is a collection of files, which can be compressed in gz or bz2 (or many other) formats.
To install aaa.tar.gz do this:
open terminal. go to the place where the file is saved. then type "tar -zxvf aaa.tar.gz"
The file will be uncompressed and untared. Then do "./configure" and then "make" and "make install" one after another, in the folder where the files are saved.
To install aaa.tar.bz2, do the same, just replace "-zxvf" to "-jxvf". That is: "tar -jxvf aaa.tar.bz2"
Then do the usual "./configure", "make" and "make install"
I dont get one thing though, if u cant use the internet, how come u are using this forum??
Also, get a book on linux. It will help a lot