I created my road sign model in Blender and with the help of @Reinhard I was able to get it to display in the list of models to be added to the map in ETS 2 Map Editor.
Due to the wrong location of the files in the screenshot, there was an error when trying to set it on the map. I moved it and it disappeared completely from the list of available models. Can anyone give me some advice? In the Editor log it says 'unmounted'.
Thank you very much,