how to make 2D sprites skeletal Movements

Hi,

I new on this unity, i have a question about the 2D sprite movements(Skeletal Animation)..

How to make a 2D character skeletal Movement without using a plugin, third party software.. Only Unity?

i have Head, Body and Weapon Sprites but the problem is this is not connected to each other... ex.. when i tried to play the body moves but the head is not followed..

Hope you help me!