here is a reference link for the Mux chanels by name and Logical Chanel Number
Now look up what chanels the Mux is relaited to here click Example
Mux 1old RF chanel Number
62will bring up the following chanel group
see link above
LCN 1 BBC 1
LCN 2 BBC 2
LCN 7 BBC 3
remember LCN means Logical Chanel Number
Mux is the range that it covers
RF is the old UHF chanel numbers of the past
so, MUX 1 = UHF chanel number 62
see links above