How do you replace a opel corsa barrel?

To replace the barrel (ignition lock cylinder) on an Opel Corsa, start by disconnecting the battery to prevent any electrical issues. Remove the steering column covers to access the ignition assembly. Insert the key into the ignition, turn it to the "on" position, and press the release pin to remove the old barrel. Finally, insert the new barrel, ensuring it's aligned correctly, and reassemble the steering column and reconnect the battery.