How to upload your own icon to the map?

We created a hiking map at OSM and had our own icons created for it, which we now want to load into the map. The icons should be uploaded as URLs. We did that, but the icon still doesn’t appear. What did we do wrong? Does it have to be a certain format?

Thank you very much for your help!
Kind regards

can you post the URL of “OSM” where you uploaded?