I just want to know what tools ect I need

The back glass repair is not for the feint of heart. It can be done, but it’s not something most end users will get right without inflicting additional damage to the chassis. Experience is a non-negotiable prerequisite for this repair; screen swaps do not count as this is a lot more difficult.

Anyway, the guides to open the phone and strip it down can be found here. Once stripped, you will need to heat up the back glass to break the bond and use adhesive remover to help release the broken glass if it's being difficult. Do this SLOWLY or you will damage the chassis and need a replacement. There are no guides on this here, so refer to this video.

For the sake of avoiding chassis damage, I usually recommend a case for less experienced users. It hides the damage and doesn't risk the phone's chassis. Just don’t get a clear one, since it will expose the damage.