how do you close all the open horisontal tabs at the top of the home page?

If you want to close all those tabs at once, try right-clicking one of the tabs and choosing “Select All Tabs,” then right-click again and select “Close Tabs.” Just be careful not to close the whole Firefox window by mistake. If you only want to get rid of a few tabs, you can also select them individually by holding Ctrl while clicking on them.