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As noted in the documentation:

Do not try to overwrite one Joomla! version family with a different one. Overwriting a major version with another (e.g. restoring a backup taken on Joomla! 3.7 on top of a site running Joomla! 2.5 or vice versa) or between different minor versions (e.g. restoring a backup taken on Joomla! 3.7 on top of a site running Joomla! 3.6 or vice versa) will NOT work. Joomla! moves files around between minor and major versions. Since the backup does not delete files not present in the backup archive this will end up with Joomla! being "confused" and malfunctioning. In these cases you should delete the existing files and folders (except, perhaps, user generated content) before restoring the backup. You can safely restore a sub-minor (path-level) version on top of another. For example, you can safely restore a Joomla! 3.7.5 site on top of a Joomla! 3.7.3 site or vice versa.

https://www.akeeba.com/documentation/akeeba-backup-joomla/restoring-backups.html#general-guidelines

Make sure you have a copy of all your backup archive files somewhere safe on your own computer (and, ideally, on a flash drive not connected to your computer, just in case your finger slips or something). Delete the files and folders under your site's root. Then place kicsktart.php and the backup archive file(s) in your site's root. Run Kickstart and proceed with the restoration.