There's nothing much to installing JLib:
You'll need to reboot if you alter config.sys, but you knew that already.
The source code and files for building the library are in the file X:\JLIB\JLIBSRC.ZIP. If you're not interested in the source, you may delete this with impunity. Otherwise, unzip it from X:\JLIB. You can also delete the sample directory if you wish.
You may find it useful to preserve the JDebug sample: make it & copy JDebug.exe somewhere on your path. This program acts as a runtime trace window for the library; see Errors.