You could try searching for a video on how to do it. There are lots of them out there. If that doesn't work, you can always call a professional to do it for you.

There are a few ways to attach gutter covers. One way is to use screws or nails to attach them directly to the roof. Another way is to use brackets that fit over the edge of the roof and then the gutter cover attaches to the bracket. The third way is to use a hanger that attaches to the gutters and then hangs down below the eaves of your roof and the gutter cover slides onto the hanger.