Add to Chrome.
Click 'Add extension' above.
The installation process should take less than a minute.
Next, you'll Create an Account.
How do I automatically sync changes between shared sites?
The sharer (the person sharing the site) must be Premium, and they can choose to have updates to the login synced automatically back and forth between the sharer and the sharee (the recipient of the share).
The sharee does not need to be Premium, unless they in turn would like to share accounts and automatically update changes to their shared sites.