As an ImperialTrooper You are the Police of the Galaxy, Your Enemy are Rebels, And You will do whatever it takes to Stop them.
But You wont do it alone. You can have a Droid to help you out. Type:
/droid (you can then choose and name a droid that will follow you )
You will be able to carry a blaster, Type:
/shot get Blaster
To become a ImperialCommando You will need to obtain 15 experience (XP) points by Doing Empire Quests from Coruscant.
As a ImperialCommando You will be able to use a Sniper Rifle. Type:
/shot get sniper
To become a ImperialAdmiral you will need to do 1 very Unpleasant Job.
Speak to Senator Palpatine on Coruscant,Who will Ask you to do an unspeakable task.Complete that quest, and you will be given an Admirals Badge.
As an ImperialAdmiral You will not only be in charge of the lower ranks, but you will be able to use Airstrikes.
/shot get Airstrike
Throw the airstrike item, and get out of there asap