My antenna cable broke

I got a iPhone 6s from a guy who had this phone in a life proof case and accidentally went swimming with it. In this case the lifeproof case failed and led his phone to water damage. We took it to a repair shop and the shop damaged the wire that leads from the speaker to the screen digitizer hook up. We found the broken lead and just left it there to see if it would turn on, nothing. But there was heat where the broken lead was making contact with the exterior of the device. Leading us to believe the phone is trying to turn on. The part is 1.47 online, but we cannot get the speaker off of the iPhone to access this. Can anyone give me a set of insturcutions on how we can take this speaker off, and if this could be why the device doesn't turn on. Thanks a lot. -Caiden