Thor Hammer

I have never had or used a Thor hammer before on my knock-offs.  I have always
had the solid lead hammers.  This new Thor hammer that i got has a rawhide
side and a copper side.  Can anyone please tell me how to properly use it.  Is
there a technique that you start with one side and then finish with the other
or does it matter?

Thanks in advance for all of your comments,

Mike Carpenter