I am having trouble with Sketchup Free Web - Tool extension

When I hover over the tool bar the tools do not expand?

They’re not supposed to expand. For more tools go to the bottom of the toolbar and click on the three dots to get the flyout.

You can customize the toolbar to include the tools you use most commonly by dragging them from the flyout panel onto the toolbar.

BTW, I moved this thread as well as your other one to the correct category.