These images show a way to test with the machine open. Be very careful and do not reach into the machine! There is a risk of injury and electric shock.

There are two microswitches at the top that trigger the display's "missing powder lid" and "powder chute open" errors. Outsmart the two microswitches with two clamps.

Place an empty toilet paper roll on the grinder and put a handful of coffee beans in it.

Plug in the power and draw a cup of coffee.

Now you can observe how the grind looks (it should be quite fine-grained, almost like flour) and how much falls into the brewing chamber. Change the setting very slowly, as the effects can only be observed after two cups.

The markings on the adjusters should be at medium grind as shown. When assembling, make sure that the knob on the top cover is properly engaged with the adjuster.

Never forget to disconnect the power plug before reassembly!