My phone won’t turn on any further than the Apple logo

First, try force restarting:

Press vol up then vol down then press and hold the power/side button till the phone shuts off. Keep holding till you see the Apple logo and try again.

If it doesn't work:

Enter recovery mode:

press vol up then vol down then press and hold the power/side button till the phone shuts off. Keep holding even if you see the Apple logo, and let go when you see the connect to iTunes/connect to computer logo. Then plug in your iPhone to your computer and click Update iPhone.

If it doesn't work, click Restore iPhone instead. Restoring will erase all data, just take note.