How does the imperative work?

The imperative is used to give order or instructions to the person(s) you are talking to.

The impersonal form of the imperative is conjugated like the form you.

¡Canta tú! ¡Canta!

¡Cállate tú! ¡Cállate!

Irregular verbs are a excepcion and have to be learn individually since there is no rule to explain them all.

Salir: sal

Poner: pon

Decir: di

Tener: ten

Hacer: haz

The negative form of the imperative is formed as it follows:

¡No cantes!

¡No bailes!

¡No hables!