Getting into Pottermore...

No one knows the best time to register because the are changing the time when the clue shows up
In the case 당신 solved the clue, add the answer to the end of the web address link
That will lead 당신 to a website where The Magical Quill will be located, and 당신 have to find it, when 당신 do, they will send 당신 strait to the registration page
The 포터모어 nicknames are the usernames, 당신 can't choose your username, they give 당신 5 choices and you'll have to pick the one 당신 liked most, and yes they are related to Harry Potter