To set up QuickBooks Assisted Payroll for your company, first activate it by going to the Employees menu, clicking on Payroll, and entering your payroll service key. Then, complete the setup by adding your employees, providing the company details, adding tax and payroll items, and connecting your bank account with QB.

https://proadvisorsolutions.com/blog/quickbooks-assisted-payroll-what-is-it-and-how-to-set-it-up/