The driver configuration chain table is already prepared for up to three modules, but you have to set the LSMD ("last stepper motor driver") parameter accordingly. First, load the driver chain table. Then: For one module, set it to 0, for two modules, set it to 1 and for three modules set it to 2. Then save this setting using the "Set" button.
Depending on the revision of the base board, you might also change the setting of the CS_COMM_IND parameter. Just try it out.