Dropbox api “USER TOKEN”, “USER SECRET”

Question

I am trying manipulate files using Dropbox Api by using DropNet Client (C# version of Dropbox CLient API). Here is my code:

    var client = new DropNetClient(APP_KEY,APP_SECRET);
    client.Delete("/Public/test.txt");

But it seems I need "USER TOKEN" and "USER SECRET" as well. Where should I get these two? Updated: I just need to manipulate files in my own folders and my shared folders. I already have APP_KEY and APP_SECRET from myApp page, where can I get "USER TOKEN" and "USER SECRET"

THanks