The ID that Corvid is expecting in the queryReferenced query is the collection’s built-in ID field called “_id”. Here’s how you get it to show in the collection editor:

TeamsId is the _id value of say the first record in teams.
wixData.queryReferenced("teams", TeamsId, "child_id")
.then( (results) => {
console.log(results);
} )
.catch( (err) => {
let errorMsg = err;
} );
It returns an array like this:
In your query, the records returned would have the children data child_id, teams-2, players_first_name, players_last_name, etc.
