Llamarse = to be called, to call one's self

If you want to tell someone what your name is in Spanish you would say, "Yo me llamo______ or simply say, Me llamo." If you want to ask someone what their name is you can ask the question, ¿Cómo te llamas?  = What is your name?

¿Cómo se llaman?  = What are their or you all's names?

¿Cómo os llamáis? = what are you all's names?