Ok this maybe how it works.
You give each post a tag or two or three and if you click on one of them it lists all post that carry that tag.
Going to try and do a few on Blood and Wine.
Tags only link Posts to Posts, so although they can be added to pages, they do nothing???
They only link within the same Blog. There is a plugin that links to wikipeadia.
So it's possible to link to a search engine.