Step 1, 2 & 3: Payroll -> General -> Lock Payroll, Release Payslip/EA Form

You can choose to lock or release the payroll payment period to avoid from overwriting the payment that has been processed. 

You can lock or release by selecting the period that you would like to lock or release, then click on the lock/unlock logo.

 Payment Period

 Select the payment period group as well as the year to lock or release payment period or payslip.

 Auto Lock Setting
You can configure to auto lock the payroll payment period here. Click on the button and it will bring you to the screen below.