The 737 is a complex aircraft.
The Zibo Mod of the X-Plane 737 takes realism and accuracy to an even greater level.
This really isn't the place to learn how to fly the thing.
If you are on facebook, there are many groups that offer assistance. Zibo Community
To answer your question above, Power from the BATT is the standard state. Once you have power from either the GPU or APU, then you must select these on the Electrical BUS power panel. You have to tell the aircraft which power source to use. Once the engines are started you must then select the Engine GENerators 1 & 2 on the same panel........ I re-iterate - It's a complex aircraft