For a screenshot of how this page should look please see my according
Blog entry
from July 29, 2017.
If you see a green bar below, web components could be loaded and added,
else you should see a red bar containing error messages.
Component-1 is extern and should be green, component-2 is also extern but has no own style,
component-3 is intern and should be red.
Web components are always inserted into "host" elements. A child-element of a host can go to a "slot" of the web component which is inserted into that host. That way contents of the host and the component can be merged.