Start the room measurement
When measuring the room, first place a marker in an easily accessible corner of the room, preferably on the longest wall. Make a note of where you have placed the marker. If possible, mark the position with a sharpie. This can help you later when re-aligning the room.
Now carry out the steps:
- Now mark the first point in the corner of a long wall by placing a position marker.
- Mark or memorise the point in the room. Use a sharpie to mark the spot, for example.
A position marker is set
Great, a position marker has been set!
Now go to the next corner of this wall. The second position marker should be as far away as possible from the first, as this will make it easier to re-align the room later if necessary.
You have now moved to the right or left to the next corner. Keep this direction for further marking.
Two position markers are set
There are now two position markers here.
Now place a third position marker at the next corner, going in the same direction.
More than two brands are set
You have marked an area with the third position marker!
From the third position marker, the floor is drawn at the bottom. You will now see a blue area showing the floor within the three position markers.
Now you can switch on the 
switch on the dimension display in the tool menu.