Now that you've completed the positive aorist, it is the negative's turn.
The present continuous, past and future all have regular negatives, but the aorist doesn't.
The negative form of aorist is also constructed by adding -mE, but the aorist suffix -r turns into -z.
On top of this, the negative aorist suffix -z vanishes in the first person when using the negative.
The good news is there are no irregular verbs in the negative that you need to memorize.