Check out the below documentation. I’m assuming you are using the Web Services Connector.
Supported Operations (Web Services Connector) This page details the distinction between “Account Aggregation” (which links users to entitlements) and “Group Aggregation” (which fetches the entitlement objects). https://documentation.sailpoint.com/connectors/webservices/help/integrating_webservices/supported_operations.html
Response Mapping Configuration This section explains how to map API responses to schema attributes. This is where the attribute property is implicitly handled during account aggregation. Response Mapping
Managing Entitlements (General) General overview of how entitlements are aggregated and managed in ISC. Managing Entitlements - SailPoint Identity Services
Reverse Entitlement Aggregation & WSAO Rules - issue when entitlements are aggregated before accounts, and provides advanced workarounds (like using “After Operation Rules”) if you absolutely must reverse the order. Reverse entitlement aggregation for Web Services connector
Account Aggregation & Entitlement Correlation Discussions on how Account Aggregation is required to “promote” raw data into linked entitlements. Account aggregation right after operation