the CBCH is the BCCH channel, combined with some SDCCH subchannels.
So the CBCH is your sole and only BCCH i the cell. Obviously, it will be on the BCCH TRX 🙂
By default, it should be on the TS0 of the TRX1.
To configure it, it is like configuring a BCCH timeslot, exceptyou configure the timeslot as being “combined BCCH”