If your musicians will be performing at a bar or concert hall, the government isn't going to care much. If, however, you hope to have your music event in a public space, like a park, you've got an additional step in your planning process: obtaining a permit.
It's possible you won't need one, but you probably will. To host an event, especially if it's a ticketed event, in a space like a park, you'll have to book it with the city, which typically means filling out paperwork and paying a fee. Without the proper permits, you risk being kicked out the space.
If your concert will be held on a campus quad, consider the university as your "city." Make sure the higher-ups know what you plan to do, and arrange for any permits they require.
Next, you've got your date and you've got your space; now you need your audience.