Your firearm should have come with an instruction booklet that tells you step by step on how to disassemble and reassemble the firearm. Once you disassemble it, you run a cloth with some CLP through the barrel. After that you run a dry cloth through it until nothing comes out on the cloth. Then take a cloth with a light coat of CLP and rub down all the parts of the weapon. Use a tooth brush or something small to get the crevices and stuff. Then take a dry cloth and wipe it down. Once you're done cleaning, reassemble it. Then dry test it to make sure you reassembled it right. If you did not get a booklet you can go to Barettas web sight and download a file with the instructions for it.
The instructions will tell you how to adjust the sights as well. Most handguns are really accurate right out of the factory though and do not need to be adjusted.
As far as hundgun basics and rule: use the same basics you were taught in the Army with the M16A2. Think about taking a class and go to the range as much as possible. Become so familiar with the firearm that it becomes muscle memory to do anything with it.
That's pretty much all I have. I'm sure you will get some people from the NC forum who will be glad to meet up with you to help you out.