How can I create and upload an iOS-Build from Visual Studio to App Store TestFlight?

The issue with the provisioning profile has been fixed.

I have downloaded and installed Transporter on Windows but I don´t know how to open it to upload my iOS file to TestFlight.

A Terminal window opens when I double click iTMSTransporter and then some text is displayed and after a few seconds it displays in the Terminal window that I should press a key to close the window.

How can I use Transporter to upload my iOS file to TestFlight?

Please see the Apple's doc -Transporter User Guide 3.3 (Install Transporter section)

Download Transporter using the link below:

Windows

Click the Microsoft Windows link to download the installation package.

During install, Transporter automatically uninstalls your previous Transporter installation, registry key, and folders. To keep your earlier Transporter installation, rename the earlier installation directories before installing the current version.

1. Double-click the self-extracting installation executable iTMSTransporterToolInstaller_3.3.0.<build>.exe, where <build> is the build number for the installation package. Follow the instructions that appear.

Read the Software License Agreement, and then click I Agree.

Select the directory where you want to install Transporter and the included files.

By default, the installation executable installs files in the C:\Program Files\itms directory, and creates a /iTMSTransporter.woa subdirectory. For consistency and ease-of-use, Apple recommends using the default installation directory.

Click Install, then click Close.

I have already installed Transporter in C:\Program Files (x86)\itms

But I don´t know how to use Transporter to upload my file to TestFlight.

I found this Quick start here but I think it is for macOS and not for Windows:

Quick start After you install Transporter, use the following steps to get up and running quickly using your iTunes Connect account (book publisher, music provider), App Store Connect account (app developer), or encoding house account for your book, audiobook, video, music, or app content.

https://help.apple.com/itc/transporteruserguide/en.lproj/static.html

In addition, I have tried to upload the file in Archive Manager in Visual Studio directly to the App Store but then I get this error. I had entered my Apple Id and created an app-specific password.

App Store bundle validation failed for archive Mygame "altool" exited with code 1.

I have already installed Transporter,But I don´t know how to use Transporter to upload my file to TestFlight.

The next step is to login your Apple developer account, then upload the ipa. In this wany, you will upload the app on Apple developer connect. And then, you can watch the video to see how to select the build for TestFlight. After uploading, you could see the Best Practice part at Apple's video - https://developer.apple.com/videos/play/tech-talks/110343/ (watch the video from the fifth minute onwards)

In addition, I have tried to upload the file in Archive Manager in Visual Studio directly to the App Store but then I get this error.

As I understand, you haven't uploaded the app to Apple developer connect.

App Store bundle validation failed for archive Mygame "altool" exited with code 1.

This error means there are something wrong with the Xcode on your Mac. Please make sure that your Windows machine paired to the mac, and Open Xcode, go to Settings->Locations, Command Line Tools, see if it is the latest Xcode version.

If you still have the problem, it's better to create a new thread so that we can focus on this new issue.