From the ‘My Collection’ menu click ‘Collection Manager’
In the left margin of the Collection Manager main page, click the arrow that appears in front of ‘Competitive Sets’ to display your existing sets.
Click the edit symbol that appears in front of the set you wish to modify. If you do not have existing sets then click 'New Competitive Set' and follow the link for Adding a New Competitive Set beginning at Step 2.
In the Available Coins column you may click to view and then select coins that are already registered to you and are eligible for the set. In this step you may also add new coins by entering the certification number you wish to add in the appropriate slot, indicate whether it is an NGC, NCS or PCGS coin.
When you are through entering coins for the set, scroll to the bottom of the screen and click ‘Save’.