Right now you can play on Taiwan and Hong Kong servers with Japan server coming soon.
When you enter login/password in game be sure to do it in lowercase otherwise it not going work.
After login for first time you need to input your secondary password. Put 111111 111111.
1. Enter https://www.alta.hk/client/unit/quickreg/
Enter www.alta.hk and press on that button
2. Press here to get code.
Select Facebook and after you been redirected press on banner with astral realm.
If it not work try to 'Like' they page (idk if it must to do or no) or get more friends (I think you need 40 friends)
If everything alright you see -
Download client - http://www.mmorpg.news/2015/06/astral-realm-hong-kong-client-and.html
VPN for faster patching/checking client http://www.mmorpg.news/2015/06/vpn-astral-realm-hong-kong-server.html
Registration Guide on YouTube -