Having trouble getting started using .net for API

Hello, I am currently working on a project in .net that is connected to some other data sources the company I work for uses. The company I work for would like to be able to add in the data from our ticketing system within Zendesk to that data.

I looked into it and quickly came upon these two packages. 

https://developer.zendesk.com/documentation/ticketing/api-clients/dotnet/

1. Zendesk API Client by JustEat 

2. .NET Client Library by Elizabet Schneider

Those are client Libraries which when looking into I need to reference somehow within my current project. Normally I am able to add the namespaces I need by adding a NuGet package or importing a .dll file. I can't find a .dll file and I've gotten every Zendesk API NuGet package I can find but I still can't seem to get this authorization snippet to work,

"Services.AddZendeskClient("https://{zendesk}.zendesk.com", "username", "token");"

and I can't seem to find references to what namespaces I can use within those NuGet packages when I try to explore what the NuGets add to the application. 

When i go through the files in those downloads it also looks like they have test files that I should be able to boot up and fill in some values then run some test queries but I always get an error that says the app I'm trying to run is a Client Library and I can't do that. Can I somehow change it to be one of those test files or something so I can run the tests?(My .net inexperience is shinning through brightly)

I am very stuck on what seems to be a basic thing. Could someone help me get my app connected using a .net core application?