How Adobe PDF Service API

Hello Everyone,

 I'm Pretty much new to Adobe PDF Services API . I just want to know how Adobe PDF Services API Working for .NET SDK?

 I have created new credentials using the below link

https://documentcloud.adobe.com/dc-integration-creation-app-cdn/main.html?api=pdf-services-api#

It Automatically generated one zip folder . I picked my zip like this

PDFServicesSDK-.NetSamples.zip\adobe-DC.PDFServices.SDK.NET.Samples\CreatePDFFromDynamicHtml

The above zip folder contains "PDFServices-api-credentials" and Private Key.

Q1. How PDF Services api working for the credentials and Private Key. in the downloaded version I hardly see any API Url to interact with PDF Services API. ? 

Q2 : What is the Purpose of this JSON ?

{
"client_credentials": {
"client_id": "",
"client_secret": ""
},
"service_account_credentials": {
"organization_id": "",
"account_id": "",
"private_key_file": "private.key"
}
}

Can some one reply to this how pdf services API Working as a collective thing?