Recently I saw the following profile:
I am wondering how it is possible to use Magic Weapon and Familiar at the same time. Can anybody explain?
You need to enable elective mode. You enable it through the options menu:
After enabling it, you can put any active skill in any active skill slot, which is the main attack (left mouse button), secondary attach (right mouse button) and the four active skills (1-4 keys).
You can, through key binding, change the default keys for the skills.