When a customer applies a discount when placing an order, an order adjustment group summary is created. An order adjustment group summary is a record that represents a modification to the order amount, such as a discount, a surcharge, or a tax. An order adjustment group summary can have one or more order adjustments, which are the individual modifications that are applied to the order or the order items. An order can have one or more order adjustment group summaries, depending on how many types of modifications are applied to the order. Reference: Order Management Objects, [Order Adjustments]

Explanation
Three components that can be used to modify the user experience in the Order Summary detail page are:
Tabs. Tabs are a type of component that allow users to switch between different views or subpages on a record page. Tabs can contain other components, such as charts, reports, or custom components, that display different information orfunctionality related to a record. The administrator can use the Lightning App Builder to add and customize tabs on the Order Summary detail page to give users more options and flexibility.
Accordion. Accordion is a type of component that allow users to expand and collapse sections of a record page. Accordion can contain other components, such as fields, related lists, or custom components, that display different information or functionality related to a record. The administrator can use the Lightning App Builder to add and customize accordion on the Order Summary detail page to give users more control and visibility.
Related List-Single. Related List-Single is a type of component that displays a single related list for a record. A related list is a list of records that are linked to another record by a relationship field, such as lookup or master-detail. The administrator can use the Lightning App Builder to add and customize related list-single on the Order Summary detail page to give users more access and context.
Verified References:
https://help.salesforce.com/s/articleView?id=sf.lightning_app_builder_components.htm&type=5

Explanation
The best thing for the customer service representative to do in this situation is to wait until the Order Summary is created. An Order Summary is a record that represents the financial summary of an order that is received from an external system, such as B2C Commerce or B2B Commerce. An Order Summary is created after an order is ingested into Order Management, and it triggers various flows and processes for order fulfillment and payment processing. A Pending Order Summary is a temporary record that indicates that an order has been received but not yet processed by Order Management. A customer service representative cannot service an order until it has an Order Summary record. Verified References:https://help.salesforce.com/s/articleView?id=sf.order_management_order_summary.htm&type=5

Explanation
Two ways that an administrator can query Order Summaries using APIs in Workbench are:
Platform API. The Platform API is a set of REST and SOAP APIs that allow developers to access data and functionality in Salesforce from external systems. The Platform API includes various resources and operations for querying, creating, updating, or deleting records in Salesforce, such as Order Summaries.
The administrator can use the Platform API in Workbench by selecting the REST Explorer or SOAP Explorer tabs, and entering the appropriate request URL and parameters.
Composite API. The Composite API is a type of REST API that allows developers to execute multiple subrequests in a single HTTP request. The Composite API includes various resources and operations for batching, tree, sObject collections, or transactions in Salesforce, such as Order Summaries. The administrator can use the Composite API in Workbench by selecting the REST Explorer tab, and entering the appropriate request URL and JSON body.
Verified References:
https://developer.salesforce.com/docs/atlas.en-us.api_rest.meta/api_rest/intro_what_is_rest_api.htm
https://developer.salesforce.com/docs/atlas.en-us.api_rest.meta/api_rest/resources_composite.htm

The Single Location High Volume sample flow and the Multiple Locations sample flow are two examples of how to implement order fulfillment with Order Management. The Single Location High Volume sample flow is optimized for performance and scalability, but it only supports one fulfillment location per order. The Multiple Locations sample flow supports multiple fulfillment locations per order, but it has lower performance and scalability. To support both high volume and multiple locations, an admin can download both sample flows from the Partner Community and make a blend between them, considering trade-offs such as complexity, maintainability, and customizability. Reference: Order Fulfillment Flows, Partner Community