Blueprint rotation

Hello, I am new with un4. I want to rotate a leg 90 degree then it works clockwise(just like our leg).
I know it is not hard.
I see all the comment related to this problem.
but my leg rotates from the middle point not from the joint.
second when it rotates it stack.so I think it is not work properly

Sounds like you did not place the pivot correctly in the modelling program.

thanks,I know I should add pivot.but I do not know which function I must use(for example rotatingmovement ,…) ,and where I put it?

In the same software you modelled the mesh.