Dimension setup problem

Hi all,
I just started learning librecad last week. I tried to set up the dimension however, the arrow is too small. It can be seen only if I zoom in. Similarly, the dimension is too small and when I zoom in then I see only a box. Even if I increased the length factor, nothing is seen. Do you have any idea where that problem might be?
In order to understand the problem, I attach image.





Thank you very much for your assistance.

Probably the distances are very large,is it about a property? Your units are mm so you get a large number for a length. You can keep all settings as out of the box except "General scale", here you should set the reciproke value of an appropriate drawing/printing scale. So for a property drawing maybe 1:100, 1:200 ? Then set General scale at 100 or 200.

Thank you very much for your help. I reset it and now it working.