Old series, old version of Minecraft. Save-files are no longer available.
How to add the save-files into Minecraft
The zip-files have been created as a backup with Minecraft Backup Assistant. If you're using that, you can throw the zip-file into your backup folder and "restore" the world with the Minecraft Backup Assistant like it was your own backup.
Or you can manually unzip the contents of the zip into a new folder (e.g. 'World1' or 'Zemalf's World' or anything you want) in your Minecraft save folder.