See the READ.ME file for possible updates about installation procedures.
There are two `areas' (directories or folders) on your system that are involved in installing /: an / source files area, and a / input files area. All files in the inputs subdirectory of the / distribution should be placed in the / input directory or folder on your system. Consult your / documentation if you don't know where this is. (You could also try looking for the file article.cls; the place where you find it is almost surely your / input files area.)
All other files in the / distribution (the ones in the math and classes subdirectories) can be placed in an / source files area; if you are installing / for the first time, create a new folder or directory for this purpose.