Best way to ask users to upload multiple files [on hold]

I am having issues with the step where we ask for users to upload multiple files.

These are the 2 main issues: - Our system is quite old so we only can use the old way to let users to upload files ( browse file -> select file -> confirm to upload)instead of the current drag and drop box - 50% of users upload sufficient files even though we have clear instructions on which types and how many files they need to upload.

Do you have any suggestions or examples on some good layouts for uploading several documents on one page ( especially mobile view)

I attached the screenshot of the page

Cheers,