Maybe you have not connected all the wires. If it is not of this then you will need programming pairing which only Apple does, and because you replaced the screen yourself they may not do it because it is Apple .
It is metal covered with glass, however i don,t recommend this phone if you want a strong one a video from the channel jerryrigeverything the back glass broke dramatically after only the second from lap fall . If you a good powerful phone i would recommend the xperia xz premium.