Once you access the settings page and click on the publishing settings tab, you get a list of information that you then configure. The explanations for those fields are as follows:
Publisher ID: For this process you will have to register at https://iatiregistry.org/user/register and go through their process for the ID
API token: https://iatiregistry.org/user/register register here and go through the process for API token.
Unsegmented/segmented publishing: To choose whether to publish segmented file(s) according to country or region or to publish the file in an unsegmented format to the IATI registry. By default, AidStream publishes unsegmented file to the IATI registry.
Automatic publishing: Whether or not to automatically publish your activities to the IATI registry once an activity is published within AidStream. By default, AidStream does not publish your activities to the IATI registry.