It’s pretty basic and just covers basic setup & including dependencies. Is there something specific you’re wanting to learn how to do with maven? You can do quite a bit with it.
btw, Sponge itself is going to be using gradle (a newer build tool). You’ll probably get people posting here saying to use that instead, so you may want to look at tutorials on both and see which you like better. Gradle uses groovy-ish for config so it may feel more natural compared to maven’s XML configs.