The thick white coax cable in photo 2 is where you will connect your VM equipment. The cable already has an adapter connected to the plug on the end of the cable.
You should be able to push-fit the cable from the Quick Start kit onto the screw thread on the end of the thick white coax cable. It will probably be a tight fit to push it on.
The coil of cable in the lower part of the box is an old telephone wire for the landline. This is no longer required as VM landlines now connect from the back of the VM hub.
Should should be able to refit the lid and the trailing wire to the VM equipment should drop out from the hole at the bottom of the box.
In the past the wall boxes used to contain a large metal isolator like this
https://community.virginmedia.com/t5/QuickStart-set-up-and/Old-NTL-socket-internal-orientation/td-p/...
but more recently the metal box has been replaced by an isolator within the connecting leads (the white plastic 'tube' below in first pic)
https://community.virginmedia.com/t5/Networking-and-WiFi/Adaptor-for-old-wall-box/td-p/5461115
