What happens after I change the log level to debug in the docker-compose file in my server? How can I start debugging

I am very new to both servers and Docker. I am trying to have a jwt authentication in my web app (Jitsi-meet is integrated). But I couldn't do it. Then I was suggested that I change the "prosody" variable's log level to DEBUG. And thus I did.

version: '3'
services:
prosody:
        image: jitsi/prosody:latest
             .
             .(bal bla)
             .
             .
        environment:
            - AUTH_TYPE
            - ENABLE_AUTH
            - ENABLE_GUESTS
            - LOG_LEVEL=debug
             .
             .
             .

However, I do not know what to do after this. How can I activate this debugging?

the point of using environment in docker-compose is to set some variables that are available to the running container and it can use them to do different things(they are nothing to do with Docker itself). if you want to debug your service you have to use this command docker-compose logs <name-of-service> which shows you both standard error and standard output of the running container(service) and use it to see what goes wrong.

from Documentation

docker-compose logs [options] [SERVICE...]
Options:
    --no-color          Produce monochrome output.
    -f, --follow        Follow log output.
    -t, --timestamps    Show timestamps.
    --tail="all"        Number of lines to show from the end of the logs
                        for each container.