When you start a band one of the first things to work out is who is going to be its leader. The leader of the band usually calls the rehearsals, work out ways to make promotional material, book the band him/herself or talk to booking agents, set up auditions and pretty much be the contact person for the band. In some groups, one person usually gravitate toward the leadership role. Other members don't mind as leadership can be quite the responsibility. In this type of band the most common trouble comes when it's time to decide which music will be chosen and performed. Most people will only show their concern about whether their own song or choice of covers will be performed or who is going to sing and play the solo parts.
Sometimes a group may have one person who acts as the music director, another handling the equipment, a third who owns the vehicle for transport, a fourth person booking gigs. In these groups the band usually splits the money as well as the responsibilities.
In other bands one person might own 'the band name' and hire other people to fill in the empty slots.
There are many different ways bands come together and they all have different purposes.
Are you a cover band doing tunes that are already on the charts? Or are you an original band developing the writing skills of the members? Sadly, cover bands will have quicker access to work. But if you don't write songs or perform originals there is nothing that will set your band apart from any of the other bands.
Now come up with a name for the band. Figure out a rehearsal schedule and find a place to practice. decide how often you will have rehearsals as well as who is going to be at them. Chances are other members in the group may have other commitments, like school, jobs, sports, spouses or boyfriends&girlfriends. So get to know your future band.