I try to align a single paragraph to the right (Right align), but it Right aligns the whole chapter no matter how I make the selection.
Put the cursor in the paragraph. It's not necessary to select the whole thing. In fact, you shouldn't "select" anything.
Use the right-align tool. Either the right-align button the menu bar, the menu (
Format > Align > Right), or the keyboard shortcut (Ctrl+Shift+R).
See my before and after screen shots below.