The Phoenix is built to utilise the boxcar as much as possible ( hence the size of the installer) this means however that the Boxcar MUST BE INSTALLED into the SAME simulator for the phoenix to run.
If you are using the P3D installer and are not using Version 4 you will need to point this installer to your simulator in the choose directory page.
If you are on Version 4.4 and wish to try and use PBR then use the PBR installer. The PBR installer is ONLY for Version 4.4 and above of P3D. DO NOT INSTALL THIS FOR OTHER SIMS. It wont work. PBR is just a method it doesnt mean cross platform cross gaming.
Otherwise please the read the manual. If you post onto internet forums with a question that is easily answered by reading a few pages in the manual... Well Jimmy Stewart will have some stern words for you.
FSX
P3D
Please not that this P3D version only offer the install into V4 if you use versions 1-3 you can locate this manually during install.
P3D with PBR