I'm trying to make shapes from the shape options on the left of screen but they are only showing as dashed lines and disappear when I go elsewhere on the page. How do I get a square or rectangle to have a solid line?
thanks in advance.

That's called a stroke. You can find it's style in "Fill and Stroke" palette. You read about the details in the Inkscape Guide. As a beginner you might like to look through the examples early in the guide.