Setting up Wordpress from the Docker image on Qnap

I am trying to setup a docker image of Wordpress on my Qnap and clearly have no clue what I am doing. I am stuck at the first few steps… Since it is an image shouldn’t the database already setup? Is the database host still “localhost”? What is the username and password? Or is this all something I am supposed to be setting up somehow?

Thanks for any advice or direction pointing!

Are you following a tutorial to do that or how do you try?