Add-On Aircraft Question...???

I have downloaded The following aircraft from Sim-Shack:
Piper Arrow..., Cirrus SR22-GTS... and the Honda Jet...
These aircraft show up in my aircraft options in the FSX Free Flight section, but when I go to fly them there are no panel gauges, aircraft colors...???
I did use a program called "Add-It" to try to automatically install add-ons that I saved in a zip file on my desktop, but I didn`t have any luck with that either...
Is there something I am doing wrong or not completeing...???
I downloaded a Cessna C152 from "Insider" and it installed itself perfectly and I can fly it anytime, so I`m perplexed as to what I have or haven`t done...
Any help would be greatly appreciated (I`m a real newbie with this add-on stuff) as I am looking forward to "Flying" some new aircraft...
Thankyou guys & gals for any help...
oldave...