While you are on the site, in your browser find and click "Add to Home Screen" A CGN beaver app icon will then be created to your phone that is directly link to the site.
Note: This feature may not be available in some browsers.
On my old 2289, the sight was held on by friction only. So try twisting it a little on each side then pulling it out. The barrel end has a notch cut into it that matches with the inside of the sight, but not perfectly.