Before attempting to restore messages
Current chat history will be lost upon restoration.
There are only up to 7 days worth of backup files.
Any new messages sent/received after a backup, and deleted before the next backup, cannot be restored.
If you run a manual backup, it will overwrite the most recent automatic backup file.
On newer devices, your WhatsApp/Databases folder is most likely located in your device's internal memory.
You must have the same phone number in WhatsApp that you had when you backed up your chats.
2.If you still can not use
Detailed guide to get your deleted text messages on Android device
When you deleted some data on the Android phone, it don’t means the end of the world is coming! You need calm down and power off your phone. Next you can concentrate yourself to find a way to retrieve the deleted texts. I introduce you a powerful data recovery tool for Android, EaseUS MobiSaver for Android. You can use the software to find your lost messages on your Android phone easily. It won’t take much of your time but just 3 simple steps.
Hope it helps