Congarts! Basic step is done. After the register of the company you should start advertising it! Find places where people enjoy the music, are searching for music, love music e.t.c. and tell them about your site! Try free and paid advertising. Advertise in many ways, internet, newspapers, T.V., radio, mails.. So customers will know about your site and visit it, them you should just manage it very very well and put effort on it ;)