Objective-C is hard and I try to stay away from it. But to use other languages such as Swift or even C# with Xamarin, you should at least have a basic knowledge and understanding of Objective-C. We can save the Objective-C for another post.
This is to show an example of how to call the Parse server using their REST API that sends a push notification to a device. You must install the RestSharp client for this to work.
// Output "BEGIN" to console
Console.WriteLine("BEGIN");
// Build Request URL
var client = new RestClient("https://api.parse.com");
var request = new RestRequest("1/push", Method.POST);
// Build JSON string to send to server
string json = "{\"where\": {\"deviceType\": \"ios\"}, \"data\": { \"alert\": \"Cubs Score: " + score + "\"}}";
// Output json to console
Console.WriteLine(json);
// Build Parameters and Headers to send with request
request.AddParameter("application/json", json, ParameterType.RequestBody);
// Enter your App ID and REST API Key from your Parse account. Login and go to Settings and Keys.
request.AddHeader("X-Parse-Application-Id", "APP ID");
request.AddHeader("X-Parse-REST-API-Key", "REST API KEY");
// Let the Parse server know you're sending JSON
request.AddHeader("Content-Type", "application/json");
// Execute the Request
IRestResponse response = client.Execute(request);
// Get the response back from server
var content = response.Content;
// Output "END" to console
Console.WriteLine("END");
Hopefully this helps get your push notifications to work. Please let me know if this works for your app.