I watched the video and it's the Painless360 one and I've seen before. The trouble with those is that he's pretty much learning the Taranis as he goes along so he doesn't set thing up in the most practical way or show you the shortcuts you can use to edit the settings. The videos are free to watch, well produced and clear so that's fine but they kind of leave out how best to set things up which, imo, is what you want as a beginner.
Typically you would want the lowest rate on the up position because that is the "safest" and it's the default power on switch check position.
So for example to set AIL rates in switch A
Edit the existing AIL line on the INPUT page first set the lowest rate weight to, say 60, and edit the switch to the UP position SA^
Long press MENU to see the DISPLAY view to test your change with the SA^. If you move the AIL stick you will see it only goes from -60 to +60. Press EXIT to return to the edit screen.
Then EXIT to the INPUT page and the copy the AIL line.
EDIT the copy and set the next highest rate weight to, say 80 and set the switch in middle position SA-
Long press MENU to see the DISPLAY view to test your changes with SA^ and SA-. Notice what happens if you put SA in the down position SAv.
The problem is that the two AIL inputs are tied to the SA^ and SA- so they don't act if the switch is not in one of those positions. nothing is assigned to the down switch position, SAv so if you accidentally switch to it you'll get some default which is probably not what you expect. In fact you get no control on the AIL stick at all which is very bad and definitely not what you want. A beginner will almost certainly crash.
Press EXIT to return to the edit screen.
To fix that you could add a third AIL rate line and associate it with the switch down position SAv.
But if you don't want that you can use "NOT switch A up" !SA^ instead of middle position SA-
When you edit the switch press use the + or - to select the switch setting SA^. The press + and - together to make it !SA^ Now the rate 80 will be the case for both the middle and the down position of SA and you won't crash ... well you might be not because you mysteriously lost all control on the AIL stick when you changed rates.
Would be easier to show in a video