First ever set of instructions to be handed down? (3,12)
I believe the answer is:
ten commandments
This clue could be a double definition.
'first ever set of instructions' is the first definition.
The definition and answer can be both related to communication as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'handed down?' is the second definition.
Although both the answer and definition are singular nouns, I don't understand how one could define the other.
'to be' is the link.
(Another definition for ten commandments that I've seen is " Orders from on high".)