Everything you enter into Manager is automatically saved to your data file when you click Create or Update (after editing something). You should frequently use the Backup feature to save backup copies of the data file on a different hard drive, in Dropbox, or at least on a USB flash drive in case (when, not if) your regular hard drive fails.
You should not need a separate spreadsheet.
I don’t actually use the payroll module because of the organizational structure of my business, so others will have to provide further help.
I strongly recommend creating a test business in Manager. You can have as many as you want. Play around in the test business until you understand the workings of Manager. Then start using it for your actual business records.