How does config.yaml use the mongodb info?

I am moving from a sandbox to a dev database. I am able to restore the backup of my sandbox to my dev db, but I cannot connect cockpit to the dev db. I am trying to configure the config.yaml file correctly. In order to do so, I was looking for a little help gaining a deeper understanding of what cockpit does with the db info added to config.yaml. Just an FYI, I have to use certificates to perform a mongorestore from the terminal if that clarifies anything. Thanks ahead!

my current db for sandbox info from config.yaml is below:

server: mongodb://username:password@host:port/DBname
    db: DBname