Basic introduction about how to create connection to data source please find here How to connect to Content Data-source?

Contentful Delivery and Management API connection

Connector uses two separate API connections to function properly:

• Delivery API is used to fetch content (there could be used Delivery API to get published content or Preview API to get latest version of draft content). Both this APIs provide fast read-only access to Contentful. 
  You can find more information about Content Delivery API here. Default base URL is https://cdn.contentful.com
  You can find more information about Preview Delivery API here. Default base URL is https://preview.contentful.com
  
• Management API is used to deliver translation. 
  You can find more information here. Default base URL is https://api.contentful.com  
  
  Parameters:
• Server/Alias(Required) - API Base URL ;
• Password(Required) - API key;
• Database(Required) - the name of the space;
• Select portal - Contentful environment;

If all options specified properly "Select portal" dropdown will contain list of all environments available for specified space.