A greenfield SAP implementation is typically a part of a large-scale business transformation project that includes new installations of SAP Enterprise Resource Planning (ERP) applications. Greenfield SAP implementations on Amazon Web Services (AWS) differ from SAP on AWS migrations, because there is no existing server footprint on premises or in the cloud to migrate—instead, new servers are sized and provisioned. Additionally, greenfield projects tend to have a broader scope technically and functionally. Because greenfield implementations are less common than migrations, it is generally difficult to find guidance for these projects.

https://docs.aws.amazon.com/prescriptive-guidance/latest/sap-greenfield-implementations/welcome.html