Did anyone notice that the genius in that video never mentioned that after the water supply is turned off the next thing to do would be to drain the tank BEFORE BEFORE BEFORE you loosen the tank bolts.
The ole Kelebay Klipper would have never overlooked that very important point.
I'm on dial-up so I can't watch videos because they take too long to load.
The ole Kelebay Klipper would have snuck a peek between the tank and the bowl to see what hardware is between them before loosening the nuts under the bowl. Most tank-to-bowl kits nowadays have two extra nuts and two extra washers that allow you to take the tank off the bowl without draining the tank first. (And, that's how I've always done it, even before they included the extra hardware in the tank-to-bowl kits. And, even now, my system is arguably better because I always use brass JAM nuts, which are half the thickness of regular nuts, and that allowed me the extra space to include a rubber washer on both sides of the tank bottom.)
Here are 4 different images that Google - Image found for the character string "tank-to-bowl kit".
Why would the above kit have four stainless washers and four brass nuts unless two of the washers and two of the nuts were intended to go between the tank and the bowl?
The plastic nuts go under the tank, so that leaves the stainless nuts and washers no where to go but between the tank and the bowl.
The wing nuts go under the bowl. So guess where the hex nuts go?
And, here they pretty much spell it out for ya.
And in each case, that extra nut and washer on each bolt is there so that you can take the tank off the bowl without draining it first.
Google - Image found 729 images for "tank-to-bowl kit" and the biggest hunk of them include the extra hardware to allow you to take the tank off the bowl without emptying it first.