From the Diablo II front screen click on the Battle.net (2nd button down). When you click on this button your game will try to connect to one of the servers on the internet. [Note: your internet connection must be on for this to work.]
While your game is trying to connect to the internet servers, you can follow the progress through several popup windows.
This is the Account Login Screen. If you have an account you can enter the account name and password to access that account. In this case, we are creating a new account. To create a new account, click on the "Create New Account" button.
The first step in creating a new account is to agree to the Battle.net Terms and Conditions. If you do not agree you can not play on Battle.Net. Not much choice here. Eithe click on the Agree button or play solo.
After you agree to the Terms and Conditions, you will be presented with a screen in which you may enter an account name and password. You will be asked to enter the password twice. This is a ploy used by Blizzard in hopes you might better remember your password. We suggest you write down the name of the account (exactly as entered) and your password (exactly as typed). Don't put this on an envelop you will lose. Put this somewhere safe.
This screen is a warning that your account will be deleted if you don't use it. Take that warning seriously. They will delete inactive accounts.
This screen contains the error message "Your user name contained one or more disallowed words." I guess they didn't like the word test or perhaps the word account. In any case, if you try to use a word that Blizzard doesn't want you to use you will get such a message.
Also if you try to create an account that already exists, you will get an error message telling you the User Account name is already in use.
In this screen I enter an Account name that is not already taken. I know that because after I clicked OK, I did not get an error message.
This is the screen you will see if your requested user account name is available. On this screen enter a valid email address -- an address where you can get email. This screen allows you to register an account to an email address. The value of this is simple. If someone steals your account you can use a form on Battle.Net to reclaim your account. They send the reclaimed account information to the email address entered here. So enter a good email address.
Just for the sake of demonstration, I entered "firstname.lastname@example.org" to demonstrate that you have to type it twice.
After you create a new account you will be shown a Select Hero Class screen so that you can create a new character. It is recommended that you exit this screen. There is a slight bug in the software. To get around this bug, exit this screen and go to the next screen to start the character creation process.