The whole point of having backups is to be able to restore your site to a previous version should you need to.
Of course, we all hope that never needs to happen but, if it does, you want to be able to do it quickly and efficiently.
If you’ve been using a manual backups approach you will need to manually import and overwrite the exports you’ve previously made. If you’re not very comfortable with tech stuff it is recommended that you get some assistance before doing this from a professional.
If you’re using Jetpack you can use their Rewind service which makes it almost trivial to essentially undo any change to your site. Simply scroll down your activity log and, when you find the event you want to undo or the point in time you want to restore to click the “Rewind to this point” option and your site will be restored.