It's seriously an easy AP to use.
I have a warthog too, I still put in a very small deadzone. I only use alt hold though, I haven't gotten my head around the other ones as yet. All I do is activate the main AP switch which is a bit like an attitude hold. Then when I am approaching an altitude I want to maintain, I switch on the alt hold switch and when I reach that height, I press the nosewheel button. You will see when you have AP active and altitude hold on but not yet engaged, there will be a warning light that says something like AP hold or the like. It's on the left side of the VDI from memory.