Step 1: Open an account on the PlayStation®Network (or use an existing account).
Step 2: From the PlayStation ® Network icon on the Xross Media Bar, select ‘Account Management.’
Step 3: Select ‘Redeem Codes.’
Step 4: Enter Promotion Code. Please note that the Promotion Code is case sensitive and must be entered exactly as displayed.
Step 5: Once the Promotion Code has been entered correctly, click ‘Continue.’
Step 6: Once you accept the terms, visit the PlayStation Plus section to access the beta
That what says on the step to redeem code.