Hi mk1978,

re:
> Only challenge that I have for construction lines is that I don´t really understand
> what is the best way to offset the construction line.

After you create a construction line if you press and hold on the little tag that appears a menu will pop up and you can pick "Relocate cline" on it, here is a demo:




> Somehow I am not able to define/lock the axis that the construction lines are drawn.

If you want it to go in a world axis direction then make sure "Straight Snap" is turned on in the bottom toolbar:



- Michael