If you re-enlisted or extended while in a combat zone, your SRB is tax-free and does not need to be included on your tax return. Otherwise, it is taxable income and you will receive a W-2 reporting the information (or it may be included on the W-2 with your regular pay). If the bonus was included as income on your W-2 and you've already entered that W-2, then no further input is required.
Depending on your other income and your tax rate, you may receive a refund of some of the taxes withheld.
If it is tax-free, please double-check your W-2 to be sure it hasn't been included in error.
