This is an easy-peasy mod that does not ask for detailed instructions, since pictures talk by themselves, it only takes a piece of diffusion film, magic tape, DCfix or whatever works best for you. The stainless steel frame that holds the lens comes off unscrewing the 4 Torx T5 screws.
Neat idea !
It makes this headlamp easier to read with, and much more comfortable for close-up work and navigation in confined places, such as an home, and to light up the ground next to feet when outside (I adopt a combination of floody headlamp and thrower flashlight when hiking at night).
I like it much better this way for the use I make of headlamps.