BEST ANSWER:

Hello Bob, their should be instructions in the CE booklet that came with the goggle. It would be under the Standard Lens changing instructions, near the back of the booklet. https://www.youtube.com/watch?v=3kleQFCpVcQ is a short video on the Marshall goggle. It does not show replacement of the lens, but at 4:12 into the video we give a very quick run down of how to do the replacement.