First, make sure your BIOS is up-to-date. You can find the latest BIOS here. At the time of writing, the latest version is HN0063 so make sure your BIOS is at least that version.
It is important to reset your BIOS settings to the defaults. After everything is working, you can come back and tweak any overclock settings. After resetting the BIOS settings, we make three changes:
Disable portable device charging mode or a device plugged into the yellow USB port will prevent the computer from sleeping.
Set Thunderbolt Security Level to Legacy Mode or TB3 will not work.
Disable secure boot or Clover will not load.