The time clock is the two buttons underneath it, one for minutes and t'other for hours. Press these with a biro and the display will increment 1 hour or 1 minute at a time.
The trip computer, on the right hand stalk have a look on the front of it. There should be a switch with the legend "0 1 2 0" nearby.
The 1 is for your latest journey which resets itself after the car has been off for 2 hours.
Turn on the ignition, set the switch to 1, press the button on the end of the stalk until it shows one of the first four function, any will do. Push the multifunction switch to the left and hold, this is a momentary action spring return type switch. If you now check the display whichever function you have selected will show 0's. Leave the display set as it is.
The 2 is for overall journey which resets itself after a very long time, I'm guessing at 48 hours of driving.
Set the switch to 2, the display will now show the previous owners figures. Push the multifunction switch to the right (this is 0) and hold, if you now check the display whichever function you have selected will show 0's. Theres no need to check the others on position 2 because again they will all be at zero with the exception of the oil temp and ambient outside temperature indication.
I know it goes on a bit but I didn't want to leave anything out.