MAKE SURE you have your LastPass account setup before going through this procedure.

Once you receive the welcome email, make sure you click on the Create GravityZone password link at the bottom of the email BEFORE logging in:

The first time you click on the link, it will ask you to setup a password using the requirements listed (12 characters, one digit, one upper case one lower case and one special character) - the text will stay red until you type in an accepted password:

Enter and then retype your password. If Bitdefender accepts it, you will be able to click the Save and Login button to take you to the MFA Setup:

Scan the QR Code with your mobile device that has your LastPass account on it to add the account. The account will be added as 'Gravity+Zone+Cloud' with your account email below it.
MAKE SURE you copy and save the secret key in a safe place. This secret key will allow you to get into your account ONE TIME if for some reason your LastPass account is not working
Go ahead and type in the Authentication code and then click the Enable button.
Agree to the EULA terms by placing a check mark in the box and then click the Continue button:

Once you do so, you will be presented with the Essential Steps for creating Installations and Policies:

Although you have the ability to do so with this account, all of this is already setup and done for you. I would advise you not to make any changes to this information. You can click on the Don't show again check box at the bottom to stop this form from popping up when you log in.
Click the Close button to continue.