Samples
The best way to get started with mapsui is to download the source and run a samples app. There are sample apps for each supported platform. Try for instance the Avalonia app (runs on Windows, Mac and Linux) Mapsui.Samples.Avalonia. If you run any of the sample you will see there is a way to selected a category and and within that category several specific samples.
Running the samples will help you to see what Mapsui can do. All these samples correspond to a specific sample class that is derived from ISample (or IMapControlSample). The most easy way to find them is to search for the name of the sample that is displayed including quotes. For instance, searching for "1 Points" will lead you to the file PointsSample.cs.
Where can I find the code for the samples?
The samples can be found in this folder: Samples\Mapsui\Mapsui.Samples.Common\Maps.