On the page <https://openlayers.org/en/latest/examples/image-vector-layer.html> I copied the HTML code from under the map to `/tmp/a.html` and run `firefox /tmp/a.html`.

At first two problems appeared easy to fix:

1. SyntaxError: import declarations may only appear at top level of a module
2. The character encoding of the HTML document was not declared. The document...

To fix it:

1. replace `<script>` by `<script type="module">`
2. add `<meta charset="UTF-8">` into `<head></head>`

But what to do with the third error? 

`TypeError: Error resolving module specifier: ol/Map.js`

I have Firefox 60.0.1.

So, are the HTML codes in the examples meant to be used as I did, or did I misunderstand something?

And what do I need in my code to `import Map from ol/Map.js`?

(I tried to reformulate the question, but if I still deserve a negative ranking, please explain why. Thanks)