So when you said the code was the same as you posted before you meant except that you have now included two separate DS3231 libraries. Why both ? You're only using one of them.
But anyway neither of them contain a getTime method so I have no idea where that comes from. One of them contains readTime and one contains separate gets for getDay, getHour, getMinute etc.
So as I said you have the wrong library to go with that code. I can't see in that video where he tells you where he got his library from so you need to do some investigating (or make some changes to the code).
Steve