I followed the instructions and it asked to me to open two psql processes and call an instruction from the other which I did.
> postgres=# INFO: Let's connect keyboard. Open another psql process and enter "K1GSFJF0;"
https://github.com/Firemoon777/sql-battleships/blob/87770216...
It then queries every second looking for a session in the postgres_log for a query that matches that password and stores the session id into a table named ks_id.
Once it knows the session_id it can then listen for any input associated to that session.