Create Contingent Worker Assignment/Placement API

Hello - We are looking to create some code that would create a Contingent Worker record in EBS. We have found some of the necessary API's to create the Contingent Worker person record, but we are not finding the one that would create the Assignment/Placement for the worker. I have found one to update/correct, but that is only helpful when the record already exists. Is there an API that we are finding that will allow the creation of the assignment/Placement?

Thanks!