We recommend that a qualified instructor helps you fit the filter, however it is quite easy to do once you have determined which of your eyes is dominant. Using the finger pointing method (explained in eye dominance ) along with a colleague, determine which image in the diagram refers to you. Remember to do this a few times to get a decent average of your eye dominance. For a right hand shooter use your left hand to point, if you are a left handed shooter use your right hand to point. Once you have identified your image, you know which filter will be best suited for you. To order you filters go to eye dominance products and remember to let me know which strength you require from 1-5. please give me a call if you need any assistance, I would be happy to help.