At first, connect your phone to computer via USB cable, then start the app on your computer. Make sure your phone has been linked to computer correctly, or this data recovery problem couldn't detect it successfully.
Step2: Enable USB Debugging
You need to enable USB debugging on your device, then the data on your android phone will be synced to computer. And the problem will scan your device directly.And you just need to enable USB debugging for once.
Step3: Preview and Recover Messages
After the scan, you can preview all of your messages and contacts on an interface. And this problem could help you distinguish deleted messages with exsiting messages. Then you just need to select and check those you need to recover, and click "Recover" to save lost messages on your computer.