Don't use your LES...90% of people who attempt this get it wrong.
Use your W-2 form. The W-2 form data goes on the Wages&Income page in the software.
If you lost it...get a new copy (Big purple button :(
https://www.dfas.mil/militarymembers/taxinfo/taxstatements.html
If you've separated and didn't get it:
https://www.dfas.mil/militaryseparations/W2.html#
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*