[Plugin: SubHeading] Where do I put the code

I too am confused on where to put the code. I am fairly new with WordPress but am slowly learning my way around php… very slowly.

My site is http://www.christianityisjewish.org/newhopechapel
I’m using the template from this URL: http://mutheme.livingos.com/

I tried a few things but I still couldn’t get it to work. Could you help me? Thanks!

http://wordpress.org/extend/plugins/subheading/