Charging leisure battery from mains

Just bought first motorhome, VW 57D LWB 1995 Explorer. When charging from mains the book says there is a 'mains switch' and circuit breaker in the van. I can't find these anywere. There is a bank of switches above the seats at back, one says 'engine (up) and aux (down), which is used for charging when driving, I know this one. Is this the one used when charging from mains? If so, which position shuld it be in? Many thanks, Jan Morgan