Update email quickstart

Author: josipk-ib

email.md

@@ -1,31 +1,44 @@
 ## Quickstart
 
-#### Initialize the client with configuration
-
-We support multiple authentication methods, e.g. you can use [API Key Header](https://www.infobip.com/docs/essentials/api-authentication#api-key-header). In this case value for `ApiKeyPrefix` in example below will be `App`.
-
-To see your base URL, log in to the [Infobip API Resource](https://www.infobip.com/docs/api) hub with your Infobip credentials.
+### Prepare configuration
 
+First step is to initialize `Configuration` object to handle API authentication. In this case value for `ApiKeyPrefix` in example below will be `App`.
 ```csharp
     var configuration = new Configuration()
     {
-        BasePath = "<set your base URL here>",
-        ApiKeyPrefix = "<set API key prefix here (App/Basic/IBSSO/Bearer)>",
-        ApiKey = "<set your API key here>"
+        BasePath = "<put your base URL here>",
+        ApiKeyPrefix = "<put API key prefix here (App/Basic/IBSSO/Bearer)>",
+        ApiKey = "<put your API key here>"
     };
-    
-    SendEmailApi sendEmailApi = new SendEmailApi(configuration);
 ```
 
-Before sending email messages you need to verify the domain with which you will be sending emails.
+Now we can initialize Email API client.
+```csharp
+    var sendEmailApi = new SendEmailApi(configuration);
+```
 
-#### Send Email with file attachment
+#### Send email
+We're now ready for sending our first email. Note that response contains `BulkId` property which may be useful for checking the status sent emails. 
 Fields `from`, `to` and `subject` are required, also the message must contain at least one of these: `text`, `html` or `templateId`.
 
 IMPORTANT NOTE:
+Keep in mind folowing restrictions while using trial account 
+- you can only send messages to verified email addresses
+- you can only use your emails addres with Infobip test domain in following form `YourUserName@selfserviceib.com`
+
+```csharp
+    string mailTo = "john.doe@company.com";
+    string mailFrom = "<set your user name>@selfserviceib.com";
+    string mailText = "This is my first email.";
+
+    var response = sendEmailApi.SendEmail(from: mailFrom, to: mailTo, subject: subject, cc: null, bcc: null, text: mailText);
+
+    string bulkId = response.BulkId;
+```
+
+#### Send Email with file attachment
 
-If you are using Infobip free trial account you can only send messages to registered email.
-Also make sure that from parameter is set to YourUserName@selfserviceib.com.
+Example below shows how to send email with attachment.
 
 ```csharp
     try  
@@ -35,13 +48,37 @@ Also make sure that from parameter is set to YourUserName@selfserviceib.com.
 
         EmailSendResponse sendResponse = sendEmailApi.SendEmail(  
                      "<set your user name>@selfserviceib.com",  
-                     "<set your test mail>@<test mail>.com",  
+                     "<set your test mail>@<verified email>.com",  
                      "Mail subject text",  
-                     text:"Test message with file 2",  
-                     attachment:attachmentFile
-                     );     
+                     text:"Test message with file",  
+                     attachment:attachmentFile);     
 
-        attachmentFile.Dispose();  
+        attachmentFile.Dispose();
+    }  
+    catch (Exception ex)  
+    {  
+         // HANDLE EXCEPTION  
+    }
+```
+
+#### Schedule Email for later sending
+
+You can also send delayed emails very easily. All you need to define is the desired date of the email delivery as `sendAt` parameter of the `SendEmail` method.
+
+```csharp
+    try  
+    {  
+        DateTimeOffset sendAtDate = new DateTimeOffset(DateTime.UtcNow.AddMinutes(30), TimeSpan.FromHours(0));
+        using FileStream attachmentFile = new FileStream(attachmentFilePath, FileMode.Open, FileAccess.Read);  
+        
+        EmailSendResponse sendResponse = sendEmailApi.SendEmail(  
+                     "<set your user name>@selfserviceib.com",  
+                     "<set your test mail>@<verified email>.com",  
+                     "Mail subject text",  
+                     text:"Test message with file", 
+                     sendAt: sendAtDate);     
+                     
+        attachmentFile.Dispose();
     }  
     catch (Exception ex)  
     {  
@@ -52,9 +89,8 @@ Also make sure that from parameter is set to YourUserName@selfserviceib.com.
 #### Delivery reports
 For each message that you send out, we can send you a delivery report in real-time.
 All you need to do is specify your endpoint when sending email in `notifyUrl` field.
-You can use data models from the library and the pre-configured `com.infobip.JSON` serializer.
-
 Additionally you can use `messageId` or `bulkId` to fetch reports.
+
 ```csharp
     try  
     {  
@@ -68,9 +104,3 @@ Additionally you can use `messageId` or `bulkId` to fetch reports.
          // HANDLE EXCEPTION  
     }
 ```
-
-Exampe of messageId:
-
-```csharp
-    messageId = "u3qre3bqdxgom8qhq4ae"
-```