It means you need to backup your personal data somewhere since the replacement phone will be new and you will have to set it up as with any new phone. Backup your pictures to Google Photos, or similar cloud storage, or to a computer. Backup your music if not already stored in cloud storage, backup all other personal files to Google Drive or other cloud storage, if you want your text messages restored on the new phone you need to back them up using an app like SMS Backup & Restore, if your Contacts are not synced with Google Contacts then you need to backup your Contacts with a file type that you can restore onto the new phone. Whatever personal data you have on your current phone that you want to have on the new phone has to be backed up somewhere, using some form of backup storage (either online cloud systems like Google Drive or on a computer). Hope that helps answer your question.