Order of appearance in folders by date instead of alphabetical?

Hello,

I update sites frequently with adding linked PDF documents to a list in order of date. I noticed with a recent update I am unable to change the order in the folder from alphabetical to list by date modified. Is there any way to change the folder to date modified or date in general? When I'm linking the PDF I'm selecting the text and dragging the arrow to the actual PDF in the folder. There are hundreds of files in the folder and in the past it was as simple as changing the view mode so the most recent was at the top. Can anyone please enlighten me as to how to make the most recent file added to the folder appear at the top?

Any help would be greatly appreciated.