var clientId = "your_client_id_here";
var clientSecret = "your_client_secret_here";
// This URL needs to be added to your 
// callback url list on your app settings page in developer.vimeo.com.
var redirectionUrl = "https://your_website_here.com/wherever-you-send-users-after-grant";
// You can put state information here that gets sent
// to your callback url in the ?state= parameter
var stateInformation = "1337";
var client = new VimeoDotNet.VimeoClient(clientId, clientSecret);
var url = client.GetOauthUrl(redirectionUrl, new List<string>() 
  {
    "public",
    "private", 
    "purchased", 
    "create", 
    "edit", 
    "delete", 
    "interact", 
    "upload", 
    "promo_codes",
    "video_files"
    }, stateInformation);
// The user will use this URL to log in and allow access to your app.
// The web page will redirect to your redirection URL with the access code in the query parameters.
// If you are also the user, 
// you can just pull the code out of the URL yourself and use it right here.
Console.WriteLine(url);
Console.WriteLine("Give me your access code...");
var accessCode = Console.ReadLine();
var token = await client.GetAccessTokenAsync(accessCode, redirectionUrl);
//we need a new client now, if it is a one off job you can just
//you are now ready to upload or whatever using the userAuthenticatedClient
var userAuthenticatedClient = new VimeoDotNet.VimeoClient(token.AccessToken);