Level 24

Total Experience Required 75,167

Level 100 progress: 1.1%

This is roughly the same as:

Killing 126 people in Warzone, or...
Killing 128 people in Execution, or...
Killing 107 people in Wingman, or...
Scoring 26,846 points in Guardian, or...
Scoring 81,704 points in Annex, or...
Scoring 49,452 points in Submission.

Horde (TU4)

Completing 188 waves on Casual, or...
Completing 126 waves on Normal, or...
Completing 94 waves on Hardcore, or...
Completing 76 waves on Insane.

Or a combination of the above. Have fun!