On the ECC side an OData service needs to be available. From this service you need to get the metadata XML file. Use this metadata XML in the Mendix OData Connector module to generate all the necessary services + domain model on the Mendix side.
Not entirely sure what you mean, but OData services need to be published and available on the SAP ECC Side. This is key in using the standard Mendix OData connector.
Apologize for being not clear, I understand that the OData connector is to be installed on the Mendix side and it is going to help browse the services that have been exposed from SAP ECC. Is that correct?
OData Connector integrates application integration with systems, such as SharePoint, databases, SAP OData services.