1993 Jeep Cherokee replacing cam shaft

I am a home mechanic and am replacing my cam shaft.
I am following a detailed removal/installation printout given me by my local repair shop.

I don't have air tools. I am having a problem removing the bolt holding the harmonic balancer. I cannot break the bolt free using a regular socket. When I try to loosen the bolt, the crank turns.

I am told that I can hold the flywheel with an approved tool and I should be able to free the bolt.

Any other suggestions, I don't want to damage the flywheel.