First step is to design the Clock Face. In best case you find one on the Internet matching to your desired Language. In my Case i borrowed a German Clock Face (First German Google Result).

But just think a moment about it. There are some Letters which are not needed to display Time, so you can define your own Letters between. Here i took some Colors to the Clock face:

I used EXCEL to do this ... but I'm sure Open Office Calc or simmilar will also do the Trick.
Next i created a Template with marking of the center of each letter.

This template is going to be transfered to the Wooden Sheet.