how to build a iterior rock wall?

Answer 1

Is very simple if you want to go with rock/stone panels.
there's few manufacturers like this one.
http://www.norstone.com.au/rockpanels.asp

and they should have instructions.

if you looking at a real stone wall, is getting messy.

Answer 2

You hire an experienced, licensed, insured contractor because the last thing anyone needs, is for some half baked rock wall to start falling on them !