Beginner Projects, Videos, Etc. for API

Are there any beginner projects, documents, videos, etc for someone who is just picking up the API? 

I am trying to develop with in on ASP.NET MVC and so far I'm having a real tough time. For example, retrieving the accounts files (which should be a simple process) Here's what I have so far. If anyone might be able to help or point me in a good direction for learning it, I'd greatly appreciate it!

I know this should be a simple task, but for some reason, when I debug the app, it just displays a blank screen. I'm not sure why I'm having such a tough time.

Home Controller
public DropboxClient client = new DropboxClient('MY ACCESS TOKEN');
public string Files = "";

public async Task<String> Index()
{
     var GetFiles Task = GetFiles();
     await GetFilesTask;
     return Files;
}

public async Task GetFiles()
{
     var list = await client.Files.ListFolderAsync(string.Empty);
     foreach (var item in list.Entries.Where(i => i.IsFile))
     {
          Files += item.Name;
     }
}