I have the basic bird plus all add-ons. This IS the Captain's flagship, it's fantastic once you get it installed and ensure everything is working.
Re: this problem - I don't have the sim open at this time, but if memory serves when you install the aircraft an option is added to your menu bar across the top of the screen, it's part of the drop-down where you can request external ground power before starting the aircraft's engines. You can use the aircraft's batteries/ATM generator as well. However, if you continue to draw power from the battery without replacing it, you will quickly exhaust it. That's what the generators are for. If you can get an engine started using the ATM, then be certain to switch on its generator there are four control switches in the middle bank of electrical system controls on the overhead electrical panel. You should also check the electrical power selector switch (rotary switch) on the right side of the same panel to ensure you have selected, first, ground power for the aircraft (if using the GPU) and, after starting the engines, select one of the generators that is associated with its engine (1,2,3,4). You'll have to ensure the generators are up and running before you switch over from the ATM generator to an engine generator, and adjust the rotary switch to ensure the power is being drawn from an engine generator. Also, on the bottom bank of controls, be sure as has been stated you have switched to the correct electrical bus for power distribution to the aircraft.