just select the next gear youre going to need, and simply stomp on the clutch when you want it to happen
:nono:
It's not a clutch pedal, it's a gearchange pedal

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The operation is completely different; when you want to change to the preselected gear, you just lift the throttle pedal, then press the gearchange pedal to the floor and release it immediately . It's a quick 'press fully down then release'; if you use it like a clutch pedal, you'll destroy the transmission in short order. It can be hard nowadays to find an MOT station that knows how to drive one, though most cars with these transmissions will be exempt now.
They're almost the exact opposite in principle to a dualogic; basically an automatic gearbox with a torque converter, but with manual control (the dualogic is a manual gearbox & clutch, controlled automatically). You drive the car just like a conventional auto, except you have to manage when to change gear. You can move the gearchange lever any time you like, moving or stationary; the change only happens when you press the gearchange pedal. When coming to a stop, you can just leave it in any gear you like and brake; the torque converter takes care of the rest. They creep just like a conventional auto.
Unfortunately they're inherently rather inefficient; the fluid flywheel torque converter saps a lot of power.
Daimler were very fond of them in the pre-Jaguar days. You can give your passengers a very smooth ride with these transmissions, just what you need in a limousine. In the days before synchromesh, this would have been a big selling point.