I followed this video and implemented it successfully.
Now, I want to know if it’s possible to display the file data in the app before adding rows to the table.
Please give more details on what you are trying to do. What data do you need?
If you need file name and size - just expand file model to get it.
If you have file ID from backend - use appropriate endpoint to get required data.
Note that there are two different endpoints available. One to get file bytes and another for file model without bytes.