If I understand what you hope to do, that’s fairly simple functionality to build - just add a repeating panel which displays each file as it gets uploaded in the ‘for’ loop. Add a button in each row of the repeating panel to optionally delete any uploaded file from the database (although I’m not clear on why you’d want to delete a file you’ve just selected to upload).
Whatever custom functionality you want to implement, you’re going to need to compose it by looping through files selected with a file loader widget. Take a look at: