i am thinking about using black box, but I have no idea how to install it. how do i do it using source or rpm?

and once i get it up and going, how do i access it or use it from the sign on screen as my desktop manager?

I will assume that the installation will be similar to FluxBox (which was based on BlackBox). From source, ./configure, make, make install, look in /etc/X11/wmsession.d, create a file 03Blackbox:

NAME=Blackbox
DESC=Blackbox (You can extend if you wish)
EXEC=/usr/bin/blackbox
SCRIPT:
exec /usr/bin/blackbox

This expects the blackbox executable to be in /usr/local/bin. If you can't find it then run updatedb as root and run locate blackbox. Then substitute the path found for /usr/local/bin.

Rebooting will cause the changes to take effect and you shound have a new, working window manager (hopefully).

you can use apt to do so, it's probably the easiest way

Not on a default Mandrake installation....

true, I should pay more attention

I know apt to be working on debian and redhat but I don't know about mandrake

you can have a look at http://freshrpms.net/apt/

Blackbox is already shipped with Mandrake 9.1. Just check your CD's