Hi, I might be being a bit stupid here, but how do I control crescendos and diminuendos in BIAB 2019 for Windows?

I can press F5 and select 'louder' or 'fade' per bar and then enter the value which, I assume, tells it how much to change per bar, but I don't know how to specify how many bars to do this?

There doesn't seem to be an option to halt the change at any point, except "back to normal" but does this revert all volumes to what they were before it started changing, or does it just stop the changes occurring?

Basically, I'd like to have a 4-bar crescendo leading up to a chorus, then keep it at the higher dynamic during the chorus, then a 4-bar fade after the chorus back to the normal dynamic for the next verse.

Thanks!