How to create an agreement using a custom workflow through the API

I am trying to create an agreement that passes 6 different workflows and generates a url using the adobe API's. I was unable to do it using the "Resources and Operations" feature that adobe has on its page. The agreement must also not send any messages pre/post to the signer that initiates it. When testing, we are always receiving a 400 error message that states either:

1.)

     {
       "code": "INVALID_WORKFLOW_ID",
       "message": "The Workflow ID specified is invalid"
     }

2.)

         {
       "code": "MISSING_REQUIRED_TO_FIELD",
       "message": "Required ToField tos is missing"
     }

We created the custom workflow and added the document in our library.

This is the JSON that we are using:

{

                "documentCreationInfo": {

                                "recipientsListInfo": [

                                                {

                                                                "recipients": [{"email": "test@mail.com"}],

                                                                "name": "Signer"

                                                }

                                ],

                                "name": "WorkFlowTestAgreement",

                                "fileInfos": [{

                                                "workflowLibraryDocumentId": "Our workflow ID",

                                                "name": "WorkflowTest"

                                }]

                }

}