You do pick it up by 'osmosis' (my God, I should be charging for it!), but with 11 hours on type, the FMS is the first thing you don't even touch! Fly it like a Cherokee- learn to get to know the performance. The FMS only gives you out as good as you program in! He shouldn't be programming, he should be flying and looking out of the window! How did I learn to fly a VC10 and 747 without using those things?
When he learns how to fly the plane and what he can do, then he can learn the refinements. But it's frightfully depressing to think a newbie learns to program a bloody computer first and then slavishly follows it first without developing his first ideas of his own!
I barely look at the FMS in the descent. I have my own idea what the descent should be like and I follow that, which is just as well because the descent calculations in the 737 are awful, and you can frequently spot errors of up to 5-7,000', which suddenly correct themselves. Below 10,000', I am just totally uninterested in it. I know how I am going to fly the approach, and I can allow for shortcuts or my own speed control. This is what he should be learning, not slavishly following a dodgy computer calculation. If he follows FMS and gets held up, or extended, his 'picture' will crumble. Then what does our young Biggles do?
All I would say he should do is draw rings at 10/30/100 miles and use it for nothing else.