Right then,

Loosen the two bolts in bright green, these go into a threaded spreader plate on the underside of the floorpan.
Now get something high tech such as a brick and jam it under the brake and clutch pedals to hold them where you want them. They should sit vertical, on the face of the pedal (ie where your foot sits).
Move the plate circled in red (that was secured by the green bolts) until both bump stops on each pedal is resting on it. Now nip up the green bolts good and tight and the pedals should stay more or less where they were being held, they will inevitably move back a little so it may take a few attempts to get them bang on.
Make sure these bolts are tight as if the plate is not help properly the force of the pedals pinging back onto the stops will slowly move the bump stop.
Circled in this photo just to give you a rough idea is the cast bump stop on the brake pedal. Also from an oval ('55), I know this as I've just taken the photo....

:)