battery ran out, connect to the Ground or start the APU.
There're whole bunch of video tutorials out there, feel free to check them out...or at least spend sometime to read the instruction.
Zibo 737 is not a "toy", it's very very very close to a study level aircraft, so it does require time and effort to get it working. If you prefer easier things to fly, go back to default 737 and you will be up and running no time.