Bed Test 9 Point Grid - First layer - Leveling

You can scale the STL in your slicer to fit the size of your bed.
I recommend to check "Uniform Scaling" and to fit the X - Y size together (arrow 1).
Afterwards uncheck and set the Z-height of the model to the height of your first layer e.g. 0.3mm (arrow 2).

The grid is two walls thick, so you can see, if they stick together all over the bed and at the end they help you to get those squares off the bed, if they stick just a bit too well.