2 / Connect to your Wow inactive account and create a lvl1 character and don't enter in-game.
Don't close your wow.exe
3/ Go to Bnet account and add your Legion Key.
4/ Add Gametime.
5/ Close Wow.exe
6/ Relauch wow account.
7/ On the Character Page, if you don't have the logo character boost lvl 100, don't close wow.exe and go to WoW Support for doing a request : Account > Game Key Problem > Contact support : Live Chat.
8/ Explain you add the legion key on your Wow account and don't have character boost. The MJ check and say i try to activated, after few minutes, the MJ say me, you just need to wait because the activation was in progress. Close the ticket.
9/ Go to the Wow.exe, connect your fresh lvl 1 character. wait maybe ten minutes, close Wow and restart !
10/ SURPRISE i have two character boost on my new account
This is my first Guide / Tips, and i hope help many people with this ...