Mood Lights are furni items that can adjust the colour of light in your room. You can make a room darker or make it a completely different colour.
You can buy a Mood Light from the Catalogue and put it on your wall. Double-click the Mood Light to access the user interface. Adjust the lights, save your settings, and ta-dah! you've changed the lights in your room.
All 4 types function the same way. The only difference is in the design, so choose the design that best fits your room.
You're probably on the Old Habbo client. The different Mood Lights are only available on Habbo Beta.
No, you cannot. You can only have 1 Mood Light in a room, even if they're different types.