The account screen contains a section that lists all the maps that belong to your account. Most customers operate just fine with a single map to manage all their layers but there are reasons why you might want to have additional maps. See Multiple Maps and Shared Layers.
How to create a new map
You must be the account manager to create a new map. You do so by clicking the "Add New Map" button on the map section of the account screen. Once the map is created you grant other users permission to add layers to the map by opening the map and selecting User Permissions. Then give those users the "Map Manager" permission.
How to change the name of a map
Open the map and select Map Properties from the map's menu.
How to set the initial viewing area of a map
Open the map and then zoom to the desired viewing area. Then select Map Properties from the map's menu and click "Use Current View".
Who Can See My Data
Multiple Maps and Shared Layers