I can't remove the cap or turn the lens!
I'm sorry the instructions reference various cameras, but if you have this one:
Then the silver cap comes off -- it is glued, but just yank it off, nothing will happen. Then you'll see the rotatable lens cylinder below it.
If you have this one:
Then you can remove the cap with force as shown below (the pictured camera is not identical, but very similar). The lens is held in a threaded aluminum tube which you can unscrew, although pliers may be required (be gentle and try not to dent the aluminum!).