The process of gathering the correct data from Salesforce is iterative. Generally, you start by examining the fields that Conga Composer® has automatically retrieved, which are displayed in the Master dataset. If those fields are sufficient for your solution, you’re ready to build your template.
If not, you’ll need to add additional Salesforce Reports or SOQL Queries as necessary to retrieve whatever data is required for your solution. For example, this additional data may include Related Lists or other data related to your Master Object, but not included in the Master Data (such as Contacts related to an Account).
After creating Salesforce reports and/or SOQL queries to retrieve your data, you add them to your solution using data gathering parameters.
While Salesforce Reports are useful to gather data for Composer solutions, it is highly recommended to use Conga Queries due to better data gathering performance, versatility, and stability.