Press and hold the power button until the power off option appears on the screen. Tap 'Power Off' to shut down your Kindle Fire HD 10 9th Gen completely.

Using a plastic opening tool, gently pry along the edges of the back cover to release the clips. Work your way around the device until the back cover can be removed. Take care not to apply too much force to avoid damaging the clips.

Locate the battery connector on the motherboard. Use a spudger to carefully disconnect the battery from the motherboard to prevent any power from flowing through the device during the repair.

Use a heat gun or hair dryer to gently heat the edges of the screen. This will soften the adhesive holding the screen in place. Once heated, use a suction cup to lift the screen slightly and insert a plastic opening tool to separate the screen from the frame. Carefully work around the edges until the screen is free. Be mindful of the display cable and disconnect it gently.

Connect the new screen's display cable to the motherboard. Align the new screen with the frame and gently press down to adhere it to the device using adhesive strips or double-sided tape. Ensure the screen is seated properly and securely in the frame.

Reattach the battery connector to the motherboard. Ensure it is firmly seated to avoid power issues.

Align the back cover with the edges of the device. Press down firmly around the edges to snap the cover back into place, ensuring all clips are securely fastened.

Press and hold the power button to turn the device back on. Test the new screen to ensure it is functioning correctly, checking for touch responsiveness and display quality.

Carefully dispose of the broken screen and any glass shards. Clean your workspace and store tools and unused materials safely.