Listen to Docker image

I am brand new with Docker, so if my question sounds too basic, I am sorry for it and I promise I am doing my best.
I did some research on the web, but no success so far.
I have an image that I can run locally, but I am struggling with the idea of how to “listen” to it on my localhost on port 3000.
I have a NodeJS code that is already listening to that same port and waiting for incoming msgs, but when I run locally, I get an error stating that the port 3000 is in use.
Any idea?