I won $10783.23 at the casino & my win/loss statement is $848.00.i filed taxes for 2015 already & got my return. what do I need to do?

If you filed your return without including the gambling winnings, you must amend your return to enter them. If your return is rejected by the IRS, you can correct the problem and fix the reason for rejection and re-efile your return. If your return is accepted by the IRS, you must prepare, print, sign and mail an amended tax return form 1040X to correct the problem.

 DO NOT change your original tax return until you start the amended return. If you have already changed it from the way it was originally filed and accepted, you must change it back before you start the amended return. Wait until you receive the refund from your original return before beginning your amended return to make sure you enter the correct amount. Here is an FAQ to help you:                                                                  

https://ttlc.intuit.com/questions/1894381-how-to-amend-change-or-correct-a-return-you-already-filed

Winnings must be entered separately from losses. Losses are an itemized deduction so the total of all your itemized deductions must be more than your standard deduction for you to actually be able to deduct the losses. To enter the winnings, type gambling winnings in the search box and click on the appropriate phrase in the drop down box and click on jump to.