Otherwise know as Freeze Panes. This feature, under the Windows menu, allows you to lock certain columns, rows, or both in place so that they never scroll out of view.
Start by locating the split bars. I don’t their technical name, but it was either split bars or doohickies. I went with the former. The horizontal split bar is just above the arrow on the vertical scroll bar. When you hover over it, the cursor changes to a two-headed arrow.
The vertical split bar is just to right of the horizontal split bar and has the same function. These bars can be moved to split the window into two or four panes.
You can scroll inside any of these panes, which can be useful, but is more often just confusing. To lock those panes into place so that their contents can’t be scrolled, use the Freeze Panes option.
The thick split pane bars now become thin freeze pane bars. You can click inside those panes, you just can’t scroll around in there and get lost. To remove, go back to the Windows menu and choose Unfreeze panes.