For the next few months, you are solely doing data entry full-time with nothing else in a windowless cubicle. After the data entry is done in a few months, you may do more interesting things. To get through this mindless slog, you:
Talk to your supervisor and ask for more work
Suck it up and work as quickly as possible to get it done
Work but half-ass it and take breaks (but don't count them on your timesheet)
Still half-ass it and take breaks but count your breaks on your timesheet
Love it! I love data entry!
Work as usual but try to spice up it up with podcasts and fill your life outside of work with hobbies, etc to keep you sane
Quit after you have found another job
*For the "ask your supervisor for more work" option, this obviously sounds like the best option for many, but you should know that even though you can ask your supervisor for work, you are 90% sure that there is actually nothing else to do and you're pretty low on the office hierarchy to be given any responsbility.