Well done!
The Esperanto word for not is ne.
It works just like in English except you always put it in front of the word that you are negating. So, if you want to say is not you say not is or ne estas. This way it is a lot more consistent than in English. You in English, you say: not me, not today, not blue but does not (should be not does*, shouldn’t it?). In Esperanto it’s always ne (something).
How would you say: