it is easy, tighten the screwnut on the side that holds the globe. you will see there's two on each side, one next to the frame ring and one under the frame, turn the screw nut clockwise (the one next to the frame ring) and then tighten the one under, usually you would just need to do one side. DO NOT over tighten
* how do you clean the globe
use soft 100% cotton cloth or microfiber cloth, you can use damp cloth for globe surface.