Hello,
This switch trusts CoS be default so if your phones tag themselves with CoS that will be fine. In the screen shot below, I manually set a port (g1) for a CoS value (4) so whatever we plug into that port (a phone in this case) will receive that priority. You can only get a little bit more complex before you have to step into an SRW series switch which will allow you to do DiffServ or Differentiated Services. Hope this helps.
Regards,
Christopher