[CLUE-Tech] I forgot how to install "tar.gz" applications

[Joe Linux]

Okay I installed Mandrake 9.1 on a different HD.  I really like it, but 
now I need to install the "rar" compression utility.  The original file 
is "rarlinux-3.1.1.tar.gz"  I also have it uncompressed (via konqueror) 
into a folder (directory) called "rar".  What do I need to do to install 
it?  I know that we went over this a few weeks ago, but now I have 
forgotten the procedure.  Is someone kind enough to tell me what to do 
again?  Right now the folder is in another directory I created called 
called /apps.