Follow the steps in this guide to replace your iPad mini 4 display assembly, including the fused LCD and digitizer glass.
This procedure involves removing the screen then transferring the home button to your new assembly. In order to maintain Touch ID functionality '''you must transfer your original home button to the new screen'''.
Depending on your replacement part, you may also need to transfer the sleep/wake sensor for Smart Cover use, this portion of the procedure requires desoldering a cable.
Parts of this guide were shot with a Wi-Fi model and as such the internals may look slightly different from the LTE model. The procedure is the same for both models except where noted.