Hi there, @gcancillerie.
I’m glad you reached out to us today. I have the steps you need to record your payroll data for last year's Quarter 1 and 2.
Since you’re using an outside service for your previous payroll, let’s enter the data by using the backdoor process. Here’s how:
1. Go to Help menu and select About QuickBooks Desktop.
2. Press Ctrl + Alt + Y or Ctrl + Shift + Y to open the Setup YTD Amounts window.
3. In the Set Up YTD Amounts window, see which documents you will need to enter YTD history for and click Next.
4. When prompted to enter the date you want your YTD entries to affect accounts, enter your estimated first payroll date in both boxes and select Next.
5. Enter your estimated first payroll date, and choose Next. This will need to be adjusted to a later date if you have trouble entering current quarter YTD.
6. Double-click each employee to enter their YTD summaries and click Next.
7. Once you have completed all YTD entries, choose Next to close the Employee Summary Information window.
8. If you need to enter payments that you've already made for taxes and other payroll liabilities from the beginning of the calendar year, refer to this link: Enter historical tax payments.
9. Click the Finish button to close the window.
For more details and screenshots, you may check out this article: Enter historical payroll data in QuickBooks Desktop Payroll.
That should get you pointed in the right direction. Let me know if there’s anything else I can do to help, I’m always here for all of your QuickBooks needs.