The hand looks weird

I’m modeling a man, and i have a litle problem.
first, i made mirrored man. After i finished, i added armature to his arms, i added ‘armature’ modifire, and i textured paint his arms to the bones.
The problem is that when i move the hands, it doesn’t looks real.

do you know how to texture-paint the arms that the movment will look realistic?

Thank you,

creating armetures are fairly complex technical tasks, you need a lot of practice, and actually moving something realistically - good animation - is a skill that takes years… just keep practicing with it and read a lot of tutorials…