Hola Sydnee! There are lots of past tenses!
The one you are describing is the preterito, a narrative tense for describing one-off actions in the past. It goes: comí, comiste, comió, comimos, comisteis (you pl. in Spain only), comieron. Endings are the same for -ir verbs, but -ar verbs go hablé, hablaste, habló, hablamos, hablasteis, hablaron.
You need to try to ensure you're stressing the correct syllable, so that hable (he speaks) is distinguishable from hablé (I spoke)
Common verbs are quite often irregular in this tense. eg ir, tener, hacer, dar, ver... You'll need to learn these separately, but there's normally a pattern. Also, look out for radical changing verbs such as pensar, which loses the i when the stress isn't on the syllable, so pienso (I think), becomes pensé (I thought), or volver, which loses the u, so vuelvo becomes volví.
All the irregularity looks a bit scary at first, but don't worry! These are the most common verbs you will use, you'll practice them a lot and will pick it up pretty quickly.