How to set up nginx subdomain in nginx configuration


In my setup everything is inside of docker containers, and I have a wordpress multisite with subdomains, that is being proxied with nginx. My nginx configuration file, has 2 server brackets for http and https, without any subdomain proxy. Everything that has the domain server gets proxied to the wordpress multisite docker instalation.

Now I want to set another docker container with a flask program, running gunicorn. The problem is that i want a specific subdomain for it, and I cant find nowhere how to set this up inside of the configuration file

What I need is that per default, subdomains get proxied to the wordpress docker container, and if the specific subdomain gets called, it gets to the flask app docker container