WebMapViewer overlays

Hi there,

currently I am figuring out how the WebMapViewer works and I am wondering if it is possible to have something like an overlay on the map.
The reason I need this is that I want multiple pins on my map with a self-designed pin to display the location of different devices and later on I’d like to draw “lines” between them to see how they are connected.

My question is if there is something I can use to realize this (e.g. a class or function) because I haven’t found anything on the Internet and if you would know a different way to build this.
Or do I need to use any google API to draw on the map?

Furthermore how does the webmaplocation work in detail, since I only found a way to pin a place on the map with adding “?q=” to the API key but I also need properties from webmaplocation like .title or .icon which is not realizeable with the way I display the map right now.