Are the following documents are up to date: https://www.nuxeo.com/blog/qa-friday-download-files-attached-documents-rest-api/ and https://www.nuxeo.com/blog/qa-friday-upload-files-documents-rest-api/?

Please correct me if I am wrong. Currently I have successfully uploaded file using three rest api steps with POSTMAN:

1. create batchId with http  POST   http://<DOMAIN>/nuxeo/api/v1/upload/
2. upload file  POST http://<DOMAIN>/nuxeo/api/v1/upload/<batchId>/idx
3. Create document POST http://10.204.20.153/nuxeo/api/v1/id/de72f8e6-348e-477b-8824-9b1c157b4f7d
    {
        "entity-type": "document", 
        "name":"nameOfDocument", 
        "type": "File",
        "properties": { 
            "dc:title": "Title", 
            "dc:description": "Created via a so cool and simple REST API", 
            "file:content": {
                "upload-batch":<batchId>,
                "upload-fileId":idx
            }
        }
    }

What is difference between POST http://localhost:8080/nuxeo/api/v1/upload/

What should I use? Is anyone can provide some examples(any programming language) with uploading file and binding to the document and download file attached to the document. Any help will be appreciated.