diff --git a/DummyClient/DummyClient.csproj b/DummyClient/DummyClient.csproj
index 19a06c7b74efeeb14ad19ee6669c555a54ee35d8..63a4a9668b6b05f9f8b1f69a46226f7e9a9a2623 100644
--- a/DummyClient/DummyClient.csproj
+++ b/DummyClient/DummyClient.csproj
@@ -17,4 +17,10 @@
       <PackageReference Include="Microsoft.Extensions.Logging.Console" Version="6.0.0" />
     </ItemGroup>
 
+    <ItemGroup>
+      <None Update="Test.pdf">
+        <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+      </None>
+    </ItemGroup>
+
 </Project>
diff --git a/DummyClient/Program.cs b/DummyClient/Program.cs
index a03392e17bcf968517fb625105b9a019572210ff..df66cb892359ede6cf5de492a9ae22ed3789b7fc 100644
--- a/DummyClient/Program.cs
+++ b/DummyClient/Program.cs
@@ -4,27 +4,34 @@ using FitConnect.Models;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Logging.Abstractions;
 
-var clientId = "";
-var clientSecret = "";
-PublicKey publicKey;
 ILogger _logger;
 Client client;
 X509Certificate2 certificate;
 
+var destinationId = "aa3704d6-8bd7-4d40-a8af-501851f93934";
+var leikaKey = "urn:de:fim:leika:leistung:99400048079000";
+var clientSecret = "rdlXms-4ikO47AbTmmCTdzFoE4cTSt13JmSbcY5Dhsw";
+var clientId = "73a8ff88-076b-4263-9a80-8ebadac97b0d";
 
 void FluentSenderCall() {
-    client.GetSender()
-        .WithDestination("destinationId")
-        .WithServiceType("", "")
-        .WithAttachments(Array.Empty<Attachment>())
+    
+    new Client(
+            FitConnectEndpoints.Create(FitConnectEndpoints.EndpointType.Development),
+            clientId, clientSecret,
+            logger: _logger).GetSender()
+        .WithDestination(destinationId)
+        .WithServiceType("ServiceName", leikaKey)
+        .WithAttachments(new List<Attachment>() {
+            new Attachment {
+                Id = Guid.NewGuid().ToString(),
+                Content = File.ReadAllBytes("Test.pdf"),
+                MimeType = "application/pdf",
+                Description = "The description of the attachment",
+                Purpose = "attachment"
+            }
+        })
         .WithData("{\"data\":\"value\"}")
         .Submit();
-
-    client.GetSender()
-        .WithDestination("destinationId")
-        .WithServiceType("", "")
-        .WithAttachments(Array.Empty<Attachment>())
-        .Submit();
 }
 
 void FluentSubscriberCall() {
@@ -38,23 +45,23 @@ void FluentSubscriberCall() {
         });
 }
 
-var logger = LoggerFactory.Create(
+_logger = LoggerFactory.Create(
     builder => {
         builder.AddSimpleConsole();
         builder.SetMinimumLevel(LogLevel.Information);
     }).CreateLogger("FluentSenderTests");
 
-logger.Log(LogLevel.Information,
+_logger.Log(LogLevel.Information,
     "This is a dummy client to demonstrate the usage of the FIT-Connect SDK for .NET");
 
 
 client = new Client(
     FitConnectEndpoints.Create(FitConnectEndpoints.EndpointType.Development),
-    "clientId", "clientSecret",
-    logger: logger);
+    clientId, clientSecret,
+    logger: _logger);
 
 Console.WriteLine(
     "This is a dummy client to demonstrate the usage of the FIT-Connect SDK for .NET");
 
 FluentSenderCall();
-FluentSubscriberCall();
+// FluentSubscriberCall();
diff --git a/DummyClient/Test.pdf b/DummyClient/Test.pdf
new file mode 100644
index 0000000000000000000000000000000000000000..50a038977b732f8c86889b164166410d5d60e0de
Binary files /dev/null and b/DummyClient/Test.pdf differ
diff --git a/FitConnect/FluentSender.cs b/FitConnect/FluentSender.cs
index 435d19d554b97b41d1070ce313992c34bd6b7d3b..90d2a71b851d681c28f5100945aef44496d24582 100644
--- a/FitConnect/FluentSender.cs
+++ b/FitConnect/FluentSender.cs
@@ -26,7 +26,8 @@ namespace FitConnect;
 ///     .Authenticate(clientId!, clientSecret!)
 ///     .CreateSubmission(new Submission { Attachments = new List() })
 ///     .UploadAttachments()
-///     .SendSubmission(new Metadata(), new Data());
+///     .WithData(data)
+///     .Subm@it();
 /// </code>
 /// </example>
 public class FluentSender : Sender, IFluentSender, IFluentSenderWithDestination,
diff --git a/FitConnect/Models/Attachment.cs b/FitConnect/Models/Attachment.cs
index d51ee26ab40566f8e249929d285ae6e74225be11..8d1a1cc1bc06a8cf14063aea573985a10c30ad1b 100644
--- a/FitConnect/Models/Attachment.cs
+++ b/FitConnect/Models/Attachment.cs
@@ -6,7 +6,7 @@ using FitConnect.Models.Api.Metadata;
 namespace FitConnect.Models;
 
 public class Attachment {
-    public string? Id { get; init; }
+    public string Id { get; init; }
 
     public byte[]? Content { get; init; }