Important: during the signup process, you will have to choose a BIM One key - like a password. This is what will allow you to activate the addin manager, and use the installer. So, make sure you choose a BIM One Key before pressing 'Save' on the registration page.
Here's what the addin manager looks like:
Quick demo of using the addin in Revit 2015:
From the BIM One site:
Here are the steps to install the application:
See more at: https://bimone.ca/Apps/Product?productId=8#sthash.vcuO5zSl.dpuf
Virtual Construction and Technology BIM One Inc. - NWC Batch Export