I have tried to get my head around this. It's not that I don't understand the whole source/sink thing, and it's not that I don't get the big idea - that when you add CL to your Desmos activity, what happens during the activity depends on what the student does - I get that. I love that. It gives Desmos that conditional property that I use so much in GeoGebra. I WANT THAT.
I think it's the syntax that escapes me. I wish someone could just make a diagram about that - this goes here, this needs brackets...anyway if I ever figure this out I shall try to make something like that myself so other people in the age range in which I find myself have a chance.
So for now I'm trying again, starting with the Desmos CL documentation. I'll also use Jay Chow's (@mrchowmath) resources, and this treasure trove of a collection that Jocelyn Dagenais (@jocedage) shared with me.
Wish me luck, I'm going in.