Hi Ohio,
Firstly - don't panic! Everyone has the same reaction to this sim, as it is the most advanced add-on.... it doesn't even use the default systems such as AutoPilot, it has it's own design from scratch.
But moving on - yes, I agree, the documentation (like most add-ons) is quite poor and doesn;t get you going anywhere in a hurry. It will take you some investment in time to get to know this plane but it will be worth it. No product available for FS9 depicts an Airliner with more reality than the 737NG.
Ok - Before worrying about starting the engines properly using the APU and everything, I'd suggest you take the "Dark & Cold" option OFF, if you have that set on FS.... then when you load in a new flight, the engines will be starting just as the simulation launches. If the engines are off, then a lot of people don't realise that CTRL + E does in fact work on the 737NG, but there is a catch :-
You need to press CTRL + E to start the auto engine start sequence, but you then need to click on the YELLOW WARNING LIGHT (almost immediately), on the left hand side of the 2D panel.... this will allow the plane to complete it's auto-start sequence and you'll be away. If you do CTRL + E but don't then immediately hit the Yellow Warning Button, your systems will not start properly :-
- You'll have no AutoThrottle, and
- You're Yaw Dampers and some other hydraulics won't work.
Give it a go, see how you get on, at least then you'll have the engines started and can try hand flying her....
A couple of other pointers before you take-off.... :-
- If an alarm sounds everytime you move the throttle, it's the FLAP CONFIGURATION ALARM... if you set flaps to 5 DEGREES this alarm will go away and you are free to Taxi and take-off.
- AutoPilot is complex on this plane..... it's pretty much identical to the real 'New Generation' AP system.
- Best thing to do for starters is to set things up on the grounds... Enter your initial altitude (try 6000 first), enter 250kts into the AutoThrottle Speed dial.... When you are straight on the Runway, set a RUNWAY HEADING (Straight ahead).
- Now take off, get to your transition altitude (About 1800) feet and hit the AP button (either), now select HEADING AND LVL CHG (Level Change)... LVL CHG is a great CLIMB system that manages the climb at a level that maintains the Airspeed.
- As an alterntaive, switch the AP on, select Heading, then press ALT, immediately followed by V/S..... this will mange your climb at the illustrated Vertical Speed and once the plane reaches it's target altitude it will level out.
This is only touching the surface of this AP system - just to get you flying... the real magic is when you use the LNAV and VNAV systems.
Hope this gets you moving - if you have anymore specifics, just shout up.
But don't give up - this plane is a bad headache at first but when you master it, it is a plane that will really make you feel like you are flying a real life Airliner.
GOOD LUCK !