There are a total of 8 terminals and they are all accessible after you complete the DLC mission. After you complete the mission, you'll start at a room (not spoiling for you) where the terminals are located.
Dossiers - When you enter the room, on the left
Investment Opportunities - When you enter the room, on the right
Delivery Pickup - Walk across the room, it's in the middle next to the spoiler-free person.
Advanced Training - Turn left from Delivery Pickup
Armor Locker - Take the short stairs up from Advanced Training
Video Archive - From the Armor Locker you'll see a door to your left. Go through that door to another room, it's to the left on a small platform. There's also a music datapad in the room next to another spoiler-free person, but it's not counted as a terminal.
Upgrades - Exit that room and turn left.
Survey Information - Take the short stairs down from the Upgrades and it's on the left next to a round table.
Note that you don't actually have to do anything fancy with the terminals; just approach them, press A to activate and exit the terminal. Most of the terminals are found also on the Normandy, so there's little chance those have anything new for you. Some of them are new and contain some relatively cool stuff - check them out if you have the time.