I can't play music in succession in my car

[AC Question]

I downloaded my music from my laptop to my galaxy 4 cell phone and it went to file folder. If I set up my phone by blue tooth to my car stereo I have to choose a song and when that song is finished, I then have to go back into the file folder to choose another song. It won't go to the next song automatically. What must I do to play my music in succession?