Searching by date created attribute in the MediaBay (Full window)

I don’t know how to search by date (attribute: creation date or modification date) in the MediaBay. I don’t know exactly what I should type next to the “matches” field, because when I type the date in any format, the search does not work.
Thank you very much in advance.

The question is that, when I do a search by creation date, through the contextual menu of each sample, once the search is done, some numbers appear that are supposed to be equivalent to the date. But I don’t understand the relationship between those numbers and the date, so that I can enter the date I want to search for.
You can see it in the attached screenshots.
Thank you very much in advance.!