You need to go to the Student Services building and talk to the Department of Student Life...there you'll need to get an Activity Planning Form (APF) and fill it out with everything you'll need.
Department of Student Life
101 Student Services Building
(517) 355-8286 fax: (517) 353-5495
stulife@msu.edu
I also had to personally talk to someone named to Robin Matheson get my event approved and whatnot.
Robin Matheson
Booking Manager
Campus Living Services
102 Mayo Hall
355-3487
OHBookings@mail.hfs.msu.edu
What I did for the first event was emailed Robin Matheson on what I should do. Basically I would just ask her first and she should lay everything out for you since it's kind of confusing.
Also, for the representing group/club, use "Super Smash Bros. Club". I don't know if it's still an active group on the Student Life website but just try it anyways. If it needs to be active again, I can relinquish my "President" title to you since you are still there.