To upload sales agreement data into the system, the administrator needs to follow these steps in order:

Insert Sales Agreements: This creates the sales agreement records with the basic information such as account, contact, start date, end date, and status.

Insert Sales Agreement Products: This adds the products that are part of the sales agreement, along with the planned quantity and revenue for each product.

Insert Sales Agreement Product Schedule: This specifies the schedule for each product, such as the frequency, start date, end date, and quantity for each period.

The other options are not correct because they involve updating the sales agreement data instead of inserting it. Updating the data requires the data to be already present in the system, which is not the case for a new implementation. Also, updating the sales agreement product schedule is not necessary if the schedule is inserted correctly in the first place. References: SalesAgreement | Manufacturing Cloud Developer Guide, SalesAgreementProduct | Manufacturing Cloud Developer Guide, SalesAgreementProductSchedule | Manufacturing Cloud Developer Guide, Import Data into Manufacturing Cloud