Start the engine manually

HI, just wondering how can i start the passenger aircraft from scratch. Ok, you know when you shutdown the engine manually buy cutiing off the fuel right? instead of ctrl+shift+F1. (i don't know if that actual procedure to shutdown the engine) if im wrong, tell me how? Ok, once you shut it down, all the screen blank and the altitude ball indicator is dead too. leave it for 10 or 15mins? When i trying to start engine manually by clicking on the 1st engine but before that i make sure all the genrator is up and running, and the Battery is on. once i click on the engine button. it won't do anything. not even ctrl+e. its totally dead. so tell me how come it won't let me. did i forget something?