If the author has allowed it then the stack/ePoster will have its own chat thread.
Click on the chat icon and you will be prompted to sign-in. You can create a free local Learning Toolbox account or sign-in via social media.
You will then be able to view any chat messages that have been posted to the stack/ePoster and send your own message. You can also choose to turn on email notifications if you want to receive emails when new chat messages are posted to this ePoster. The email notifications will be sent to the email address that you used when signing in to Learning Toolbox.