Easy, just carefully screw it onto your lens and keep it there at all times. It’s a good idea to loosen it now and then so it doesn’t seize up.
Because a UV filter doesn’ affect your camera settings, you don’t need to do anything with it once you’ve put it on your lens. Most photographers use a UV lens filter to protect their lens glass – especially if they have an expensive lens. UV lens filters prevent dust, dirt, rain, and grime from coming into contact with the lens glass.