Hi @obywanna–happy to help, but can you first change the topic title to something more descriptive so that others can be helped in turn in the future? Thanks!
For an example, here’s a bit from the Rules:
Titles of threads should be as descriptive as possible in one sentence. “Need help” is not acceptable and will be removed or changed. “What module can extend a gate signal?” is a better title.
the difference between multiply and sum, is exactly like you learned in the school (but applied to voltages) , depending of the case you will prefer use one or other.
considerate this: if you have a first voltage, and you add as sum a second voltage , the result voltage always will be an offset of the first one
multiplying voltages work a bit different for instance if one of the voltages is zero, the result always will be zero until the initial voltage change , also decimal matter , if you multiply a voltage by 0.5, you will get half of the first voltage , and so on
perhaps it could be interesting to read
there are lots of modules to allow you to know what voltage are you getting in a signal
from the scope to one of my fab hovering value
for all the 1 to X in you list, you can connect whatever arbitrary number of cables in a output
for all t the X to 1 in your list you could mix whatever arbitrary number of cables (using mixers , sum, etc ) then, connect to the input
one more thing, there are not difference between the nature of the signals, all them are voltages, you can use a module for all purpose, you can use the unity (for instance ) to mix cv ,audio , triggers or whatever