The first thing to do is to go into the main directory of the OCERA tree, it should be /usr/share/ocera_x.x (x.x = ocera version) if you have installed your system with an OCERA ISO image or in the sub-directory ocera_1.1 if you downloaded the tarball of the version 1.1 of OCERA.

Then, assuming you have a graphic environment, generate the configuration file with:
make xconfig

If you do not have graphical environment, you can use the semi-graphic configuration menu with:
make menuconfig
or even the bare text configuration menu with
make config