Problem in bone tutorial

I followed the instructions in this tutorial:
https://wiki.synfig.org/Doc:Basic_Bone_Tutorial

and when i finished and started moving the bones the layers of the arm are not moving together and get
separated and it is a big mess

please…what i am doing wrong?

i wanted to attach the file that i made but I am notified that I am a new user and do not have permission

Hi, good day or nigth.
Maybe this can help to you: