Link I.d (secret Code)

Ok. Now I know what you are referring to and can offer some assistance (I hope)

The following link shows how you can retrieve your Link I.D.

Import Old Account On New Device

Once there you will see two subheadings. Click on the option most relevant.

Option A: How do I import or move an old account? Choose if the old device is available to access your I.D.

Option B: I got a new device. How do I recover my old account? Choose if the old device is not available to access your I.D.

Hope this helps and wish you luck at the games!