Here is the step by step instructions on how to Backup Data in Samsung Galaxy Tab S3 using Samsung Account;
Configure backup and restore options using a Samsung account.
Step 3 : Touch SIGN IN to log in to Samsung Account or CREATE ACCOUNT.
1- Is it necessary that we will not lose data after creating backup?
NO, it is not necessary that we will not lose data after creating backup, because the frequency of losing data is very less. Google stores all the data in is cloud storage that gives assurance that we will not lose the data. If you lose your Google account and forget the password, then you can recover the password. So there are very less chances of losing your data or files.
2- Isn’t restore factory reset harmful to your smartphone?
No it is not. Restoring factory settings in Android phone simply brings the phone back to the state it was when you purchased it. Though rooted phones remain rooted, factory reset erases all data, gets rid of other issues like lagging issues, frees up phone memory and more.