Suppose you have a module whose sources are in the current directory.
umake produces urbiengine-linux-remote, a remote object executable
umake-lib -o mymodule produces mymodule.a, a library that can be linked using umake to a sdk.
umake-engine -o urbi . libs/othermodule.a produces urbi, an URBI server containing the module othermodule.a and the module made by compiling the sources in the current directory
umake-engine --core=aibo --host=mipsel-linux produces urbi, an URBI engine for aibo which can run on the aibo host. This is the same as umake-aibo
umake-engine -H arm EXTRA_CPPFLAGS=/usr/local/myLib/include produces urbiengine-arm, an URBI engine for arm architecture containing your object, if you have the arm-engine URBI SDK installed. It will search for headers in the /usr/local/myLib/include directory.