Hi Jim. Here's how I do it. First you need to extract the zipfile to a Temp folder in the same way as a downloaded aircraft. Open the extracted folder to examine it. All panels consist of a Panel.cfg file + one or more BMP images. These should be in a folder named Panel. (Open the Panel folder of any default flyable aircraft to check how they're configured.) If the files are not already configured for install, create a new folder named Panel & drag the Panel.cfg & BMPs into it. (If in doubt I always refer to the default files.)
To install the new panel to an existing aircraft, open its folder & back up the existing panel by renaming the Panel folder to Panel.1 or similar. It doesn't really matter what you name it. Now paste the new Panel folder into the aircraft.
Most 3rd party panels will include their own gauges. These will usually be in a folder or zipfile named Gauges or similar. To install the gauges open this folder, click Edit/Select All & paste the complete contents into FS2002\Gauges. Do NOT overwrite files/folders if prompted.
Most downloads will include instructions. It's always a good idea to read these first even if you use your own methods to install the files.
Hope this is some help. It's really not difficult when you get the idea.
PS. I'm assuming you already know how to install a new aircraft. If not, this tute should help.
http://www.simviation.com/acinstall.htmThis one covers panels.
http://www.simviation.com/paninstall.htmBoth tutes are posted in the SimV Help section. Also check out my Lair from the link in my sig.