How does one go about importing an offline or historical data feed of purchases into Marketing Cloud?
Reading the documentation I know it can be done: https://help.salesforce.com/articleView?id=sf.mc_pb_catalog_faq6.htm&type=5#mc_pb_integration_with_contact_builder
Reading other stackoverflow pages I see someone recommended making the conversion call: Einstein Email Recommendations - historical purchase data
But the documentation says historical purchases should come through in a catalog format. If so, where in the UI do I import historical purchases?
If I am supposed to do it via SSJS, is the process to convert every purchase to a Conversion Collect call as described on this page and then run it via an SSJS activity in automation studio? https://developer.salesforce.com/docs/atlas.en-us.mc-apis.meta/mc-apis/pb-collect-tracking.htm