Thank you for choosing QuickBooks Online, DT1974!

We're partnering with KeyPay for our payroll service in QuickBooks. I'd recommend reaching out to them to help you in entering your employees historical data. You can reach them by going to Employees and clicking on the Payroll support button in blue at the lower right-hand corner.

On the other hand, you can check out the article about setting up and processing pay run for your reference in the future.

If you have other questions, you can always visit us back in the Community.