I do not know what that means and how to trigger the supposed extra time
thanks in advance, GeertDS
First number is time for the game in minutes, second number is "increment", additional time bonus per move in seconds. Thus e.g. "30+20" means 30 minutes for the game plus 20 seconds for each move. In OTB games, this increment is added to clock in the beginning and then after each move (when you push the clock lever/button). On lichess, the clock is only started before each player's second move and increment is added after each move, starting with second.
thank you very much for explanation that is clear now
