From the Tools menu, go to NuGet Package Manager and click on the Manage NuGet Packages for Solution... menu. In the Browse tab, search for Newtonsoft.Json and install the NuGet package. Newtonsoft.Json is a high-performance JSON framework for .NET. Once it is installed, you will see that the reference Newtonsoft.Json has been added to your project, References.

In the using statements for your class, add the following namespaces using Newtonsoft.Json; and using Newtonsoft.Json.Linq; to your code.