Here’s your link of the day, explaining in graphic detail just what all those levers, switches, knobs, and lights in a plane cockpit are for. I’m only halfway through it and am fascinated by all the workings of an airplane.
Above the lever are three landing gear lights. They’re green when the gear is down, red when the gear is in motion or not fully extended, and unlit when the gear is up. It’s typically a good idea to check for “three green” before landing.