Engineer

You are the Engineer. The keeper of the flame, the holder of power, the digger of sand, the ultimate utility-man. Your job is to keep the base looking like a base and less like a gazebo after every raider attack. Coordinate with the Rangers to get supplies you need from the local area to maintain your crazy bonfire builds without leaving the safety of your calm walls.

Being the Engineer
I'm Gonna Start off with saying that you may have picked the Most Important Jobs in the NCR. More important than the LT. Don't let it get to your head though. 1.Gather Tools Find a Laythe (or something) and go get some tools if you don't already have tools. 2.Gather Materials Go grab a LOT of metal. You're gonna need a lot of metal for wall & shit 3.Dig Some sand You're gonna make a lot of sandbags. They're honestly the easiest thing to make, so you should really considering building your defences with them first, and then upgrading them in patches. 4. Secure the Compound Airlocks are your best friend. They're the only real way to prevent random wastelanders from entering the base when nobody is looking.

A general wall of... something should be a goal. Firewalls (a long line of bonfires) are one of the more effective methods of base defense 5. Upgrade or Die Weather you like it or not, you are in a endless arms race with enemies that will get stronger the longer it takes them to attack. As an engineer, there is no real point where your job ends, as the base can always get stronger.

Your job ends when the conflict ends, but even then, we'll still have use for you, engineer.

Chain of Command
You're in the middle of it.