Question

how do i connecting 16.4.2 Ai whit an RM16 Ai mixer for more inputs and how does it work

Answer 1

A RM16AI does not give you more inputs. It serves you as stagebox or in I/O mode it works as an indepedent monitor mixer with 8 mix outs. Cascading two SL1642AI would offer you 32 input channels, but not more than 6 mix outs (aux).