The wiki has am in depth tutorial which covers the autopilot, too.
Thanks, I'm glad to say that I completed a short flight successfully, Innsbruck to Salzburg, and got the altitude captures sorted.
The big challenge for a new user here is the interactive cockpit, as zooming in to click the Autopilot buttons means losing wider visual references to the outside and the flight instruments. So its a constant back and forward as you learn and check the effect of your AP inputs.
I am still a bit confused about AP on the Q400 as activating one mode seems to disengage another. But its early days, I'll try another flight tonight.....