I would also like to suggest that in future you research your purchases first, especially with animals such as anemones that have such a dismal record in captivity.
First step would be to search our library,
http://www.reefs.org/library (do a search specific to the bubble tip as well as BTA), then search the Advanced Aquarist database. Be ready for a long set in front of the computer for that session, as that database is HUGE. In both these searches you'll find information on lighting as well as feeding, and the experiences of others.
You can start with small bits of squid, silversides, krill (I would remove the shells), shrimp, or allow some fishfood to float into its tentacles. Be prepared, once it's fed, for it to shrivel and expel slime, this is normal for many, if not most, anemones.
I will also point you to another site with pages specific to BTAs,
http://www.wetwebmedia.com (there is a Google search bar at the bottom of the page, simply enter the search terms as you will here, and you'll be taken to a Google page with links within the site). The information will
mostly be questions (FAQs) from others such as yourself, with answers from the crew, but I believe there are one or two articles as well.
Good luck! (And remember to get up and walk around whenever you lose feeling in your behind.
)