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.
Take the butt pad off - should be a phillips head. Then inside (this may be where something is sliding around) you will see a flat head / bolt head that holds the butt stock to the receiver. This is not exactly rocket science.
Nothing should be sliding around inside and you should determine what it is.