I have also had a look at this one. The general procedure of installing textures in any MSFS has been the same since before FS2002 - BUT!!
This one looks like a whole pile of effort - certainly not a user friendly file. I have installed and tested 1000's of files over the years. I even used to design the odd aircraft for FS2002 and this one looks like it would challenge me too.
If I were you I would just find individual liveries for your default FS2002 747 and install them. There should be lots available. (can't quite remember if FS2004 liveries can also be used in FS2002??)
Might save you some blood pressure!!
Think global. It's the world we live in