Using a public link is one of the methods that developers can employ to distribute beta versions of their apps through TestFlight without needing individual email addresses. If a developer provides you with a public TestFlight link, follow these steps to install the beta app:

1. Prerequisites:

   - Ensure you have an iOS or iPadOS device running a supported version of the operating system.

   - Install the TestFlight app from the Apple App Store on the device you want to use for testing.

2. Use the Public Link:

   - Simply tap on the public TestFlight link provided by the developer. It might be shared on their website, social media, email newsletter, etc.

   - This link will open either in a web browser or directly in the TestFlight app.

3. Open with TestFlight:

   - If the link opens in a browser, there should be a prompt or button to “Start Testing” Tap on it.

   - If asked, confirm that you want to open the link with the TestFlight app.

4. Install the Beta App:

   - Once inside the TestFlight app, you'll see an overview of the beta app, including its name, developer, and description.

   - Tap the “Install” button to begin downloading and installing the beta version of the app on your device.

5. Testing and Providing Feedback:

   - Use the app as you normally would. Remember that this is a beta version, so you might encounter bugs or issues.

   - Within TestFlight, there's usually an option to send feedback directly to the developer. This is essential for them to understand and fix potential problems before the official release.

6. Updates & Expiration:

   - Beta builds in TestFlight typically have a 90-day expiration. You'll need to update the app if the developer releases newer builds within this period.

   - You can check for updates directly within the TestFlight app.

7. Transitioning to the Official Release:

   - Once the app is officially released in the App Store, it's a good idea to download the final version from there. This ensures you get the most stable release and future updates.

Using a public TestFlight link simplifies the process for both developers and testers, allowing for a wider distribution and more feedback. Always remember, though, beta apps might have unresolved issues, so take precautions like backing up your data when using them.