With family access you will have the option to create a separate login for an additional family member.
This is only available to annual Membership+ subscribers.
To add another member to your account, make sure that you are logged in on the website, then you can click on My account, select Account details and then Subscriptions.
From there you can click on the Manage drop down arrow and select Manage shared accounts.
Note: Once you enter the email of the person that you would like to add to your account, you have to press enter before you can save it.