You login you playNC account.
In My Account at right upper corner, choose Apply a Code
Then you can see Scroll: Summon Storm Bundle in the Unused Serial Codes session
Click apply and I think next you need to choose server and char to receive it.
After yesterday's patch, you can directly do 2nd class transfer by 1 click and the spellbook chest and 10 100,000 sp scroll will appear in your inventory.