Example - call API operation using .NET

var client = new HttpClient();

// Set OAuth token obtained in separate call
client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", "{OAuth token}");

//Set subscription key from Developer Portal
client.DefaultRequestHeaders.Add("Ocp-Apim-Subscription-Key", "{subscription key}");

//Set URL to API operation (see API documentation in Developer Portal).
var builder = new UriBuilder("{url to API operation}");

//Set querystring parameters (see API documentation in Developer Portal).
builder.Query = "{querystring name/value pairs}";

var response = client.GetAsync(builder.Uri).Result;

var result = await response.Content.ReadAsStringAsync();