Data Pad 1:
Take the upper entrance (the mission entrance).
Go inside and follow the dirt path until you get to the first set of structures.
Here on the floor is Data Pad 1.
Go deeper inside the base and you will see Storage Container 1 right at the path.
Data Pad 2:
Follow the path and you will find Data Pad 2 on a box.
In the next area, you can go inside a room with a hand scanner. Here is Storage Container 2.
Data Pad 3:
If you go through the room, taking the other exit, you will find Data Pad 3.
It's in the main computer room.