As Ruski said "although some prior building experience is required". You admit you are a little weak in that area. Tom is quite helpful and so are the rest of us. Take a few deep breathes and relax. It's a great plane and you will like it. With that said, would you take some pictures of the firewall so we can see the hole you are talking about, plus tell us when you got the kit. I have attached a picture of my firewall and if you look close you can see the lines marking the center of the firewall. The large hole was drilled by me for airflow requirements of the carb. If you don't have the lines, than you might have an older model requiring you to center the prop shaft in the cowl. Download Tom's generic manual which shows how to do that and the rest of the how to's for his planes.
http://www.wildharerc.com/downloads/...ric-manual.pdf
Take a look at the Sukhoi manual to see if it matches the one that came with the plane:
http://www.wildharerc.com/downloads/...c%20detail.pdf

Keep us post on your progress and ask questions when needed. BTW, the real PITA on this plane is mounting the landing.

Chuck