Moving modified files to master catalog

I added a large number of pics to an existing master catalog (Pictures with Post Processing Edits). I can see the pics in that master catalog. However, whenever I sort the pics, the new ones are intermingled with older, edited photos. So, I went to the "recent imports" files in the menu (see attached screenshot) and made edits to all of the new pics. Now, when I go back to the master catalog, none of the edited pics are there, only the original files I added. I thought the "recent imports" was just a placeholder and what I was editing were the ones that had been added to the master catalog. Given the large number of edits/pics, how do I get the "recent imports" into my master catalog. Note: I did not create a new catalog for the "recent imports"'