In order to be able to enter the game, you need to create a master account, log into your personal account and create the required number of game accounts. If you already have a Game Account, but there is no MA, create a new one and click "Import of accounts."
After you created an account, you need an original Classic client.
After preparing the Classic game client, it must be updated with the last patch: Patch Update Ver.1
Check the files are up to date using the launcher. Put it in the game folder and run it!