Hi Seralar,
As requested, here is the workflow with a sample excel spreadhsheet. This requires the excel integration component that is included. If you dont want to use the same formatting (you probably wont), then you will need to create the spreadsheet the way you want to and then regenerate your own integration component to read the spreadsheet.
This poject creates the users if they do not exist, or updates them if their first name, last name, street address, or telephone changes in the spreadsheet. Default password created for the users is Password123.
This is a very rough example of what can be done. Please test, and change and modify as you would like.