There's three sizes available, 90, 140 and 190mm. Choose the largest one that fits on your printer's bed and print with your regular settings.You should cancel the print after the first layer to get a better view at how the layer turns out. Optionally, use calipers to measure the thickness of the layer at the adjustment spots to check that they're all at the same height.This design accompanies my bed leveling guides at:[EN] http://youtu.be/ED1Gxvw2Rmw[DE] http://youtu.be/qzvfg-IOQEs