Install SkiaSharp

I'm completely new to C#. I'm trying to install a package but can't figure out how. What is going wrong?

$ nuget install SkiaSharp
Feeds used:

Installing package 'SkiaSharp' to '/home/vexcess/Downloads/cstest'.
Unable to find package 'SkiaSharp'

$ nuget install SkiaSharp
Feeds used:

Installing package 'SkiaSharp' to '/home/vexcess/Downloads/cstest'.
Unable to find package 'SkiaSharp'