How do you conjugate verbs in the preterite tense for AR verbs in spanish?

To form the preterite tense of AR verbs such as cocinar you have to take off the -AR- so you are left with the stem - COCIN- and add the specific endings:yo (me) - é, tu (you) - aste, el/ella (he/she) - ó, nosotros (we) - amos, vosotros (you, plural) - áis, ellos/ellas (them)- an