An explanation of the tournament is provided down below.

A Borrel relay (also known as beer relay) is a chugging competition. You will play against another team and the winner goes to the next round. This goes on until the finale. 4 drinks will be provided on each side of the table. Every team member has their hands behind their back and as soon as the game starts the first person of each team can start chugging. When the person finishes their beer, the person holds the glass above their head and then places it on the table. As soon as the glass is placed on the table, the next person can start chugging. This goes on until the last person has put their empty glass on the table. 
The amount of rounds is decided as soon as we know how many teams participate.