Level 3

Total Experience Required 2,100 [confirmed]

Level 100 progress: 0.03%

This is roughly:
Killing 7 people in Warzone, or...
Killing 8 people in Execution, or...
Killing 6 people in Wingman, or...
Scoring 1,500 points in Guardian, or...
Scoring 4,566 points in Annex, or...
Scoring 2,764 points in Submission.

Horde (TU4)

Completing 11 waves on Casual, or...
Completing 7 waves on Normal, or...
Completing 6 waves on Hardcore, or...
Completing 5 waves on Insane.

Or a combination of the above. Have fun!