Reporting question for Vacuum Tube Retainer - Belton, for EL84s, High Quality

Product:
Vacuum Tube Retainer - Belton, for EL84s, High Quality

Question:
How does this attach to a chassis?

Answer:
Progress order of installing: 1. Insert hook to the chassis hole 2. Push and hook up the hooks to the chassis 3. Insert the vacuum tube into the socket 4. Pull up tube retainer-2 and cap it on the top of tube. Check out the mounting document for more information.