Open the Bookmarks Manager; Press the Alt or F10 key
to bring up the toolbar, and select Bookmarks.
Hot key is <Control> (Mac=<Command>) <Shift> B.

Hi MEV, in the left column of the Library window, you should find headings for all three of the main bookmark categories under the All Bookmarks heading. If those are not visible, can you find a little icon -- sometimes called a "twisty" -- to the left of All Bookmarks (or Bookmarks Menu or Bookmarks Toolbar)? That icon should open/close the next level of the list.

Once you find the folder you want to view, when you click it in the left column, its contents should display in the right column.

Does yours work that way?