I can not figure this out and have basically no idea. I have already installed MonoGame.Extended through NuGet. I have heard you can draw basic shapes like circles with it, but where can I find the method?
It looks like you can use the SpriteBatch extensions provided in the API. https://github.com/craftworkgames/MonoGame.Extended/blob/develop/Source/MonoGame.Extended/ShapeExtensions.cs
They are extension methods and if you wish to use them as part of SpriteBatch, you will have to add the following at the top of your file where you want to use them
using MonoGame.Extended; ... mySpriteBatch.DrawCircle(...)
Alternatively without using it as an extension method,