1. Create account:
https://dragon-network.net/signup
Note: For fast and sure reply use gmail.com e-mail.
2. Joining to server
Recommended way(Patched client, ready to play):
https://drive.google.com/open?id=0B3H0l_lCgfXaWS1QejBCVjNMNTQ
Alternative way:
Download autoupdater ,put it in your l2 interlude folder and run full check(Balder/Interlude):
https://dragon-network.net/download