Hello Georgis and Andros!
Welcome to the site, we're happy to have you!
That's right, you will not be able to find the "new thread" button for students now because term has already started and we do not accept new students during term. As you mentioned you had already picked up somewhere, student applications are open during our OOC ‘summer’ months: April, August, and December. Your next opportunity to apply as a student will be 1st December 2018.
In the meantime, you can apply
here as an elsewhere child and elsewhere adult. As an elsewhere child and elsewhere adult you will have access to the Elsewhere forum where you can start roleplaying your characters in places such as Residential Wizarding London or Hogsmeade.
In regard to the name-change for Georgios Ambix, if you submit a helpdesk ticket
here requesting that your name be changed to Braxton Bainbridge, an admin will be able to change that for you.
I hope that answers your questions! Of course, if you have any more questions, reply to this thread and we'll help you out!
Cheers!
Cladis