In this shot you can see the many tubes and where they tie into the front bottom of the half lateral and the footing.
In the picture below you can see were the cage is sent forward to the firewall. This is taken from under the steering wheel.
In this picture you can see the rear stays that support the main hoop on the outer bends and the rear cross bars that support the center expanse of the main hoop. Both of these sets of bars terminate at plates footings on the tops of the rear shock (strut) towers.
This picture gives you a good idea of the relation of the cage and the drivers controls. It also shows the forward components that connect to the firewall.
Taken from the passenger foot well you can see the tubes that triangulate towards the firewall. These tubes will help to keep the front half of the car from bending up into the cage. On the other side of the firewall is the back of the shock tower. You can also see the footings for the front of the half laterals (that run along the driver and passenger window/door openings) and how they are joined by the sill bar, bottom of the door x-bar, and the bar that supports the top window bar.