I'm brand new to Inkscape. I've been trying to figure out how to make an empty shape. I tried selecting the shape then clicking on the x in the Low left corner then right clicking on White in the Colors at the bottom of the screen, but it doesn't work. When I right click on White, it open a menu instead.

Start here: http://write.flossmanuals.net/start-wit ... .9/colors/

The object has to be selected -- either with the tool which you used to make it (Rectangle, Pencil, whatever), or with the Selection tool , before you can edit it in any way. You'll see a dashed line rectangle around it, when it's selected.

Once it's selected that tiny x in the lower left corner will remove the fill. (no right-click needed)

Edit
Help menu > Tutorials is a good place to start for beginners. I would suggest Basic, and Shapes, first. And note that the one titled "Advanced" is not really advanced (in my opinion). It's an introduction to paths, written for beginners.

You can also find tutorials for beginners on this page: https://forum.inkscapecommunity.com/index.php