Generate Token v2 api using c# sdk

Generate Token v2 api using c# sdk

Hello I am trying to generate a access token using c# sdk but fails every time.is there any sample code so that i can implement that code to insertleads in crm. 
my use case is i want to insert and update lead in zoho crm. when user signup in my website i insert the detail of that user in crm using API v1. but V2 api is more confusing that API v1 . so please can anyone provide me a sample code of c# sdk to generate token and insert lead in crm. Or is there any way to achieve this without using c# sdk just use simple code of c#?