The User Agent will upload a selected source file to the server that is identified in the configuration file. (The configuration file is generally coded by the application developer and provided with the User Agent. The end user will simply select the appropriate configuration file in order to connect to the appropriate server. Refer to 8.4 How to Build a Configuration File.)
The source file could be a spreadsheet or text file or even an XML file. The valid formats of the source file are defined in the configuration file. The user must select a source file that is compatible with the configuration file and the server application being used.
The structure of the source file is important and must be known. Like any data file, the file structure will be application specific. For example, if you are sending an excel spreadsheet with order details then the order of the columns in the spreadsheet are important. The columns might be line number, part number, description, price, quantity. The user would enter the appropriate data into each column of the spreadsheet to be sent. Also, the application may or may not expect to have column headings sent with the data.
It is the users responsibility to ensure that the source file is properly structured for the application. Generally, a sample source file is given to the user. The user can simply enter data into the sample file or make copies of this sample file.