During the past year, you haven't legally earned any money. However, you still have some tax oligations as an F-1 Visa Holder.
Complete Form 8843. This will let the IRS know your status as an F-1 Visa. You can download the form here.
Mail the form to the IRS by April 18th. Mail it to:
Department of the Treasury,
Internal Revenue Service Center,
Austin, TX 73301-0215