Start Up a Boeing 737 800/900

Steps

Start the battery. The battery is located toward the middle of the overhead panel.
Flip the APU (auxiliary power unit) starter switch upward 2 times, and wait about 30 seconds. The APU starter switch is located on the overhead panel to the right of the taxi light switch.
Flip the 4 APU generator switches on the overhead panel next to the cross feed and fuel pumps. Now, the aircrafts main panels should have loaded up.
Go into the FMC (Flight Management Computer) witch is located next to the throttle on the left and right side. After that, go to your upper overhead panel, and there will be two switches. turn both of them to NAV. Wait for the lights above the two switches to say "aligned". When they are, go back to the FMC, and where it says "POS INIT" click the button next to it, and when you are there, you will see a bunch of stuff.
Don't stress it, because all you need to do is on the right side there is going to be a big line of data. Click the button to the right next to that, and paste it on the line below where it says "Set IRS POS". To paste the text, simply click the button to the right of the boxes on the line below the "Set IRS POS" and click execute (just to make sure). Then, the main panels should have full color and heading/altidude/speed indicators.
On the overhead panel, in the top left corner, find a switch called the "yaw dampener". Simply switch that over to "on".
Go down to the throttle quadrant, and pull up the 2 fuel cutoff switches up. And then your done!

It might take 30 seconds or so for the main panels to get color and have the heading/altitude/speed indicators showing after you have pasted the line of the data into the boxes in the FMC.