Ok, my first newbie question

[Noodles]

My 04 has a digital fuel and temp read out (I am led to believe that these were fitted later?)
It showed my fuel and temp as like a bar chart but I started pressing buttons to see what happens    and that display has now gone and I now get what gear I am in and my temp as a figure and no fuel?


I have looked on google to see of there is a 'how to change the functions' type instructions but drawing a blank ... anyone help?


Cheers