There are two ways on how to add your TSheets to QuickBooks Desktop (QBDT). The first integration method is only available for QBDT 2018 and newer. While the second one is only available for 2018 or later.
If you're using the first method, please take note of the following:
Turn on the “Full payroll” preferences
Ensure your week start date matches in both QuickBooks and TSheets
Ensure “Use time data to create paychecks” is checked in both the Company-wide preferences and for each active employee
Ensure all employees are set up with at least one payroll item (time is unable to transfer without at least one payroll item mapped)
Be able to sign in as the main admin (username is generally “admin”)
Be able to switch to single-user mode
Be on the computer you will be using to sync TSheets and QuickBooks Desktop because the sync can only be performed in one location.
Ensure all users that need to have time exported to QuickBooks are added in QuickBooks as either an Employee or Vendor (including admins, if necessary).