UP,
U didn't say whether you'd successfully installed aircraft before & whether you understand the basic install techniques.

If you need to know how to install aircraft go to this page. It's simple but you do need to follow & understand how MS flight sims accept new aircraft.

http://www.simviation.com/acinstall.htm

If it's the specific aircraft you are having trouble with please identify the aircraft - ideally by page number & author or filename.