Simply read off how high your workpiece is and which level can be used. There are arrows next to the viewing windows. If you can see a line directly next to the arrows, you can use these levels. You can read the height of the workpiece on the back.
In this step, all parts are engraved and cut out. Please note that the ruler is duplicated and only needs to be cut out once. The second one is needed in the next step. Firstly, I recommend the front with the scaling, as this should be more accurate.
Turn the ruler so that the backside can also be engraved. Here I recommend removing the ruler and not moving the rest of the wood so that it can be lasered again in the exactly same position. Here you can make a note of the X and Y values from the front (in XCS e.g. X100, Y 126) and use these for the backside.
During assembly, the 4 pins may be too large. In this case, I sanded them minimally with fine sandpaper from the long sides. This allows you to adjust them exactly to the holes if they don't fit.
With these pins you can glue the parts together very precisely.
Finally you have to insert the ruler and you finished your scale.