The workarea is set by the configure script when it creates the top-level Makefile from Makefile.in:
Typically it is the Chez machine type you are building for, e.g. ta6le. (This keeps things from getting horribly messy when bootstrapping, cross-compiling, etc.) The make-level interface for the build system is almost exactly the same as with upstream Chez: the implementation using Zuo primarily makes it work more reliably.
I suggested make run as a quick way to get to a running Chez, but it's probably not what you want if you just want to use Chez, rather than develop it. For normal purposes, you would probably instead want to do:
./configure --prefix=/usr/local # or /opt/chez or ~/chez or ...
make
make install