How to Tag all files as new

Hi all,
I’ve installed the retention app and what i want to do is to delete ALL files regardless of type or where they are after 30 days ? We use the server to share large videos and photos to clients for them to do a one-off download and only really need them on there for a couple of weeks but if i go into the app i obviously have to select a “tag” to delete but i can’t seem to figure out how to tag all “new” files as something like “new” ? i know i can pick a file and tag it but if i upload a .jpg for example and i tag that as “new” then does it know that ANY new file has this tag or is it just any new .jpg or just files with this filename etc and does it tag any existing .jpg with this tag etc ?
Is there a wildcard or anything i can use ?