added doc link

README.md

@@ -20,6 +20,54 @@ import Combine
 import Cumulocity_Client_Library
 ```
 
+## Connectivity and basic usage ##
+
+You first need to create a Connection object and then one of the API Service classes to interact with you Cumulocity tenant, e.g.
+
+```
+let conn: C8yCumulocityConnection = C8yCumulocityConnection(tenant: "<mytenant>", server: "cumulocity.com")
+
+ conn.connect(user: "john", password: "appleseed").sink(receiveCompletion: { (completion) in
+ switch completion {
+ case .failure(let error):
+ print("Connection refused! - \(error.localizedDescription)")
+ default:
+ print("Connection Success")
+ 
+ // Now that we have tested the connections, lets fetch some managed objects
+ 
+ C8yManagedObjectsService(conn).get(pageNum: 0).sink(receiveCompletion: { (completion) in
+ 
+ switch completion {
+ case .failure(let error):
+ print("Get Failed \(error.localizedDescription)")
+ default:
+ print("Get Completed")
+ }
+ 
+ }, receiveValue: { results in
+ 
+ if (results.status == .SUCCESS) {
+ 
+ print("page \(results.content!.statistics.currentPage) of \(results.content!.statistics.totalPages!), size \(results.content!.statistics.pageSize)")
+ 
+ for object in results.content!.objects {
+ print("\(String(describing: object.id))")
+ }
+ }
+ }).store(in: &self._cancellableSet)
+ }
+ }, receiveValue: ({ userInfo in
+ 
+ print("User name is \(userInfo)")
+ 
+ })).store(in: &self._cancellableSet)
+```
+
+The above first verifies the connection and uses the `C8yManagedObjectsService` class to fetch a page of `C8yManagedObject` objects. The connection object does not carry state and
+the connect method is only useful to verify the credentials and also gather information about the user `C8yUserProfile`. Each call via the Service classes reconnects via the connection
+credentials and stateless.
+
 ## SDK Documentation ##
 
 Full documentation can be viewed [here](https://raw.githack.com/johnpcarter/c8y-ios-lib/master/docs/out/index.html)