To make changes to a data source, select the pencil icon below the data source name:

The Update data source modal will appear. You can modify the data source name or description and then choose Update.

To change the indexing configurations, select the Indexing Configurations option. In the pop-out menu that appears, enter the new settings, and choose Update Indexing Configurations.

The changes will apply to new content that is added to the knowledge base and indexed.
To change the indexing configuration settings for existing content, you can
Definitions of these indexing configuration settings and how to use them are provided in the article Setting Up and Using Your Knowledge Base.