at the beginning

I need help, I start the minecraft and when I press play it sticks to me, someone has an answer or in case I'm not the only one and sometimes I change my wifi and if it fails, it is rare that a game works through the wifi, I mean to play online but I don't understand why it sticks when playing. If someone has the problem that comments or send me a link to the problem, I speak Spanish and English in case anyone knows