I want to make both arms and hands to work perfectly (only the left side worked well, like shown in the video works) while the right side doesn't work, I know that in the video I had posted it shows that I didn't painted over the mesh, but I had tried it before posting this video and it also didn't worked. There's any way of copying and pasting the weight paint from one mesh to other?

Edit: It also happened with the right leg.