How do I backup my configuration so that in case of Computer failure, I don’t lose my configuration or historical data?

Open your configuration from the Database Builder and use Archive to archive your configuration into a single archived file. You can store this configuration on a different computer as a backup configuration.
You can either use the redundant data logging to log all your historical data on a separate computer (must map the drive), or you can use standard backup utilities that can synchronize your historian folder with its mirrored folder on a different computer.