Collisions and OnTriggerEnter troubles

I would like a collision to be a button that activates an animation when an objects hits it

please help

This is an extremely vague question. No one can help you unless you be more specific. Also it seems that you haven’t read any documentation. Read these and combine the two:

Make sure you set the game object you want to be your trigger to ‘is trigger’ in the inspector.

Good luck, in future you will get further if you are more specific and demonstrate that you have done some research on the topic.