Hi, if the display is at the top of the dash then there is a red plug under the cowling with a locking bar that secures it. This may have come adrift (it doesn't take much). The cowling just pops off.
If the display is on the radio it's sometimes made visible by turning on the radio and shining a light source on it at just the right angle.
If neither of those two apply then Renault codes start with 0000 so you know where you're starting from. Each click on the column mounted thumbwheel is one digit or each press of buttons 1 - 4 respectively will register one digit. To move between each of the four zeros consult your handbook.
Hope this helps.