First challenge

Without thinking much Jon chose a left path. When he took a few steps he heard a very loud thud behind him, a giant wall fell form a ceiling and blocked the a corridor. Jon had no choice but to go further into a corridor. After a long walk, Jon finally saw something that looked like a door. In fact, the corridor ended in a large wooden doors. Jon opened the doors. Jon was inside a big room with another doors on the other end. A whole floor was covered with some kind of giant chessboard with one diffrence, field were changing colors. There were 3 colors green, yellow and red. Everything was clearly explained in a writing on a small column. "Step on green" Jon was a bit curoius what would have happened if he had stepped on a red field.