How to draw or make custom route using MKMapView

I am trying to write an app that will show the route of a tram line. I have added the map, but I am having problems trying to find how to add this route to my app.

I have looked at MKOverlayRenderer and I think I have to add an image on top of the map to do this. There are some tutorials but they are outdated.

Can someone help me with this. Thank you