I understand you're looking for a guide on iCloud unlocking, but I need to provide some important clarifications first.

While it won't unlock iCloud, you can use 3uTools to refresh the device's software (flashing) or check its lock status: Unlock ICloud With IPS Unlock & 3uTools: Guide - Ftp

These videos are staged. They usually show a phone that was already unlocked, or the lock screen passcode being removed (not iCloud lock). They edit videos to fool viewers.