Start with the box prepared as in the picture in step 1.
Step 1: Put the device, the water bottle and the drip tray into the box as shown in the picture in step 2.
Slide the cardboard piece in (it has three compartments). Afterwards, it should look like in step 3.
Step 3: Place the CO₂ cylinder as is shown in the picture in step 3. Include the cartridge as shown in step 4.
At last, place the last cardboard piece on top, like in the last step below: