Create child theme based on main theme

I’m a newbie and need to create a child theme to apply to all pages except the home page.

Info as follows:
1. Test site is up at:https://66.147.244.156/~webmarl6/kathyd/
2. Template used: https://www.wordpressgraphics.com/search2.htm?type=17&category=0&keyword=exterex&number=&x=31&y=14
3. I need to remove the Flash animation and the third column that currently has the video at the top of it.

The layout of the middle section seems dependent on the footer code in some way, but I can’t figure out how to edit files to accomplish what I need. Any help, suggestions, is appreciated.