Tú commands provide instructions for using affirmative and negative commands in Spanish. For affirmative commands, use the tú verb form without the final "s". For negative commands, put the verb in the tú form and change the ending to "es" for -ar verbs and "as" for -ir and -er verbs. Some irregular verbs like car and g verbs undergo spelling changes, such as "tocar" becoming "toques" in the negative command.