Here in the video (minutes 05:26) a screw is selected and the arrows (construction plane) run lengthways through the screw.
When I select this one, the arrows run in the direction of X, Y and Z.
What am I doing wrong?
Hi @Nitro, you are not doing anything wrong, you just have to align the gizmo to the screw. To do that, grab the mitpoint of it with the pencil and move it to the edge of the circular top face on the screw. You will see that the gizmo will automatically be dropped to the center of the circle and aligned to the axial direction of the screw.