What do I need to replace the power button?

the entire top of my htc has come off and i've been advised to buy a flex cable to the power button as the metal thing came off and now theres nothing there

crwdns2934089:0crwdne2934089:0 crwdns2934093:0crwdne2934093:0

crwdns2934109:0crwdne2934109:0

crwdns2889612:0crwdne2889612:0 2
crwdns2934285:0crwdne2934285:0