Accidentals acting up (accidentally, I'm sure)

Accidental help.
Keeps changing within a bar! I set the first note to Bb and in the bar, it changes the next B to Natural. I went to preferences and changed it. Took a break, now I decided to do it the cheater’s way and change the key signature to F so I have a Bb as the norm. It is still putting naturals on my Bs. I change them and they come back, over and over again. So, um, maybe I input my preferences incorrectly? But where is the correct menu(s) selection to get it changed properly? I try to find it on Dorico help, Dorico Forum and in the videos I have acess to and can’t find it yet.

That is how it is supposed to work. In Dorico, each individual note has a pitch. The accidentals needed to display it depend on the context.

So if you change the first note in a bar from B natural to B flat, the other notes are still B naturals.

When you are entering notes, Dorico is smart enough to know that accidentals apply to the end of the bar, and if you just enter a “letter name” from the computer keyboard you most likely want the previous accidental to apply to it. But that logic only works for note entry, not later editing.

Think about what happens if you add some notes in Insert Mode and push a B flat from one bar into the next. You probably wouldn’t want it to automatically change into a B natural without any warning, just because it didn’t have its own accidental in the original bar!