Openlayers maps unable to pin a local version

I was able to get openlayers maps running by calling the cdn in application.html.erb (default rails 8.1, importmap and propshaft) with this line:

<script src="https://cdn.jsdelivr.net/npm/ol@9.2.4/dist/ol.js"></script>

But I would like to have it run from local on the server. I tried but the js files were not found. Which dist or package do I download and place where and call / pin / import how?

I should maybe add that the I setup a tiling server that delivers the osm png tiles for the maps in the locations views.

Oh, and merry Christmas