Before you restore from an older backup, we recommend creating a backup first (so long as your current vocabulary is how you want it to be). This way, you can always safely go back to the setup you have if the older backup doesn’t fit your needs anymore.
To restore a backup, just go to Personalization (Pencil icon bottom right in home screen) > Settings (top right) > Backup, then select “Restore Backup”. You’ll see a popup which reminds you to first create a backup. Then just select your restore file (it has a .pbk extension).