A confusion that I had at first before going further into the Openstreetmap ecosystem: OSM is not a ready to use app and some alternative to Google Maps the app, it's a lower level database on which front-ends renderings with a tileset can be built to serve different usages. If you go to openstreetmap.org you will not see much, but click on "Edit" and zoom in close and you'll get a better idea of the data layer.
Edit: to further clarify the stack, Mapbox is a collection of tools for creating maps from OSM data.
That is rather wonderful but, of course, one typically can't use telnet at work "because security". I got left with it in a mode printing escapes afterwards, and needed reset(1), but I guess that's telnet's fault, unless TERM is wrong.
I think starting with Leaflet and building from that should give you a good understanding of the building blocks for web mapping: https://leafletjs.com/examples.html
Edit: to further clarify the stack, Mapbox is a collection of tools for creating maps from OSM data.