I had Samsung s7 and now have the s9. Iv managed to transfer everything to my s9. The only problem I'm having is my what's app won't transfer my chats from my s7. Tried the restore button when I opened the what's app on my new s9 but didn't work
This may help....
If not then please try a Google Searchand or WhatsApp's own Faq's Website.
Current Phone ~
Samsung Note 20 Ultra 5G SM-N9860_256Gb SnapDragon 865+
Samsung One Ui 2.5/ Android 10.