One thing to note when you are working with multiple staves is the Active Staff. Only one staff at a time can be active, and is indicated by a black rectangle to the left of the clef symbol.
This staff is active.
Later on you will find out how to make settings that apply specifically to the active staff. There are two ways to make a staff active:
• Click anywhere in it.
• Use the up and down arrows on the computer keyboard to step through the staves.
At the upper left corner of the Score Edit window, you will find a button labelled Link. When this is activated, all other open editors will follow the Active staff selection in Score Edit. In other words, if you make a staff Active, the corresponding Part (or Track) will be automatically displayed in the other open editors as well.