If you want to know how to beat heroic Karazhan 
Silverware Golem this video by Asmodeus takes you through step-by-step.
This heroic boss is easiest completed with a Patron Warrior deck. With all of the low attack minions that keep flooding the board, you can get some crazy Frothing Beserkers, lots of armor from Armorsmiths, and plenty or Patrons.
Here is the deck list and video. Don’t get frustrated if it takes you a few attempts, the heroic levels are set at a really high difficulty and RNG can easily turn the game against you.