There are videos online of how to make this function, though it's pretty easy. If you have any issues sightmark is great with customer service, though I don't expect any as it's very rugged. You must move the ring near the eye piece to focus it to your eye. The front ring focuses the front piece on the target.
The cap in front when down allows vision during the day through the pinhole, the cap up allows vision at night. The item "Sightmark photon rt 4.5-9x42, with burris quick detach, digital night vision scope" is in sale since Sunday, July 19, 2020.This item is in the category "Sporting Goods\Hunting\Scopes, Optics & Lasers\Night Vision Optics". The seller is "iheartzombiesalotforreal" and is located in West Chester, Pennsylvania. This item can be shipped to United States.