VCV Rack Modules:
Random Source
A good general tutorial on how to use S&H modules: https://www.youtube.com/watch?v=m9auf7dpMrU
"Sample" knob is a volume control for the Sample input.
Mult
This multiplier got 3x 2 inputs and 3x 6 outputs. With the +/- switches you can decide whether the two incoming signals are either added or subtracted from each other.