To migrate a legacy install base, one must represent the products and services customers currently own. In Salesforce CPQ, tangible or perpetual license products are represented by Asset records. Services or products sold on a recurring basis are represented by Subscription records. Both of these objects are typically related to a Contract, which represents the legal agreement. Therefore, populating Assets and Subscriptions is the core task for reflecting the active install base.

A. Order: Orders are transactional records that initiate the creation of assets and subscriptions; they do not represent the final, active install base itself.
C. Quote: Quotes are pre-sales documents used during the negotiation phase and do not reflect a customer's finalized, contracted products and services.
E. Order Product: These are the individual line items on an Order. Like Orders, they are part of the transaction, not the resulting customer asset.

1. Salesforce Help, "Assets". States, "Assets represent the products your customers have purchased." This directly supports the need to populate the Asset object for the hardware/software install base.

2. Salesforce Help, "Subscription Records". Explains, "Salesforce CPQ uses subscriptions to represent the subscription products that your customers have purchased." This confirms the Subscription object's role for recurring items.

3. Salesforce CPQ Data Migration Guide (Internal Partner Resource, concept reflected in public docs), Section on "Data Migration Objects". This guide outlines that for an install base migration, Assets and Subscriptions are the target objects to populate, often linked to a parent Contract.