Hi there! I understand you're having trouble installing the LEGO Technic Control+ app for your racecar set on your Kindle device running Android 11. Since it’s an expensive set, I want to help you get this working smoothly.

To get started, can you tell me a bit more about what happens when you try to install the app? For example:
- Are you seeing any error messages during installation?
- Is the app visible in the Google Play Store on your Kindle?
- Have you tried installing any other apps on your device recently to confirm connectivity is fine?

Once I have these details, I can guide you step-by-step towards a solution.

Meanwhile, here’s a general approach to tackle app installation issues specifically for LEGO Control+ on Android:

1. Check Device Compatibility: The LEGO Technic Control+ app requires Bluetooth and certain hardware features. Some Kindle devices, even with Android 11, may have limitations or missing Google Play services that can prevent installation.

2. Update Your Kindle Software: Ensure your device is updated to the latest available OS/firmware in Settings.

3. Google Play Store Issues: Since Kindle devices have a modified Play Store:
- Open Play Store and search for “LEGO Technic Control+.”
- If it’s not found or shows “Not compatible,” this might be the root cause.
- You can try clearing the Play Store cache (Settings > Apps > Google Play Store > Storage > Clear Cache), then reboot your device and try again.

4. Install APK from Official Sources (Advanced): If Play Store is not cooperating and you’re comfortable with it, downloading the official Control+ APK from a trustworthy source (like LEGO official or Amazon Appstore) may help. Note: only do this from verified sources to avoid security risks.

5. Internet Connection: Confirm your device has a stable internet connection during installation.

If after trying those steps it still won't install, the issue may be related to Kindle’s software limitations with apps that depend on Google Play services, which Control+ uses. Let me know what you see at each step, and I’ll help you deeper!

Are you able to check the Play Store for the app right now? Or do you see any specific messages when trying to install?