Questions on RNAV,ALT and APU

Hey guys,

I'm trying to get the Hawker in the air and learn to fly her to finally make online flights with real ATC.

At all the basics are working good but some small questions coming up, maybe someone can help:

1. How to do a RNAV approach?

- it's clear to select it in the FMC but I always thought that RNAV/GPC/RNP/... using VNAV+NAV to replace the LOC+GS. But the Hawker does not have VNAV?!

2. When climbing/descending to an cleared ALT the AP is not stopping at that ALT? Correct? I'm currently mostly using Pitch for DEP and V/S for others things

3. Does the APU has any use? If I turn the APU on I have some bars lighted up for cooling but it seems that is not modeled too. Also battery seems to be affected when APU is off.

Thanks for your help

PS: Carenado if you read that...please provide better information and maybe add kinds of tutorials for users :/ This is not a common A320 everyone knows :(