is an owner's manual.
Here's what you need to do to change to MPG:
1. Put in the ignition key and turn it to the first position.
2. Press the AVG MPG button, then use a pen tip on the changeover contact in the lower right until the display changes to MPG.
When the AVG MPG is set to MPG or M/G, your date/time will be in MM.DD and 12HR AM/PM format. It's only when the L/100 is selected your date and time go to DD.MM and 24 hour format.
As far as setting date and time, it's in the manual, so that will be your "homework" assignment.