I received a reenlistment bonus of 17,500 and received 13,125 if they already took out the taxes from my bonus how to I report or file that?

[DanielV01]

It depends.  DFAS may treat this in one of two ways:  they may include it as part of your total income on your W-2, or you may receive a separate W-2 for this.  I've seen both, but it will be included on a W-2 because, as you mention in your question, taxes were withheld.  Once you have received all of your W-2's, this information will be included, so you only need to enter them into the system as printed.