The effects and gauges need only be copied to the effecs (for effects) and gauges (for gauges) folders. To install a panel you have to copy the panel's files to the SimObjects\Airplanes\"the folder of the plane you want to install the panel for"\panel. After that it should work.
If you do not want to overwrite the original panel of the plane, you can create a different panel folder and name it panel.1 or panel.mine or panel.whatever. After doing this you can open the aircraft.cfg file with notepad and change the panel parameter for that aircraft. If you named the folder panel.1, then the panel line should look like panel=1; if you named it panel.my, the line should be panel=my; if it was named panel.whatever, the line is panel=whatever.
Finally, there's one last option. If you simply want to use another airplane's panel, then you simply create a panel folder and then create a text file in that folder named "panel.cfg". After doing that, open the panel.cfg file and write this:
[fltsim]
alias=\"airplane"\"panel"
You should replace "airplane" with the name of the airplane you want to use the panel from. If you want to use a different panel from that airplane, then rename the panel part too. In the end it can end something like:
[fltsim]
alias=\Maule_M7_260C\panel
[fltsim]
alias=\Airbus_A321\panel
Hope this was useful
