The process of gathering historical data for a Windows storage dashboard involves two steps: creating a PowerShell script to collect and save the data, and configuring the Windows Task Scheduler to run this script at set intervals. The script collects data on file system drives using the Get-PSDrive cmdlet, creating a custom PowerShell object with columns for Timestamp, Drive, UsedGB, FreeGB, and TotalGB, which is then exported to a CSV file. The script specifies the CSV file path, appends new data without overwriting existing data, and excludes type information from the header. The generated CSV file includes a header row and records for each drive with their respective usage statistics.