CFD Online Discussion Forums - Some Query on Installation of OpenFoam

I want to intall OpenFoam-1.5 on Fedora Linux 11, and I am not familar with linux and OpenFoam.
I find some differrences between the guide lines on web and in the file named README. The guide line on web says:"
Decompress each file with GNU gtar and gzip using the command ”tar xzf <filename>”, beginning with the source files (OpenFOAM-1.5.General.gtgz and ThirdParty.General.gtgz - these source files must be present for OpenFOAM to be operational). The OpenFOAM source and (any) binary files unpack into a $HOME/OpenFOAM/OpenFOAM-1.5 directory. The third-party software unpacks into a $HOME/OpenFOAM/ThirdParty directory. "
But the guide line in the file README does not mention Decompressing the source files.I wonder how I can intall OpenFoam. Could some one list some steps to do so? Thanks in advance!