Daniel Gopar offers up this gem on attaching Dired files to an Org-mode tree:

#orgtip: Found this little nugget that I didn’t know existed. You can attach files from a dired buffer to an #orgmode tree.https://t.co/iTfBLHBvVm#emacs

— Daniel Gopar (@pygopar) December 19, 2021

As explained in the documentation, you can attach the file under point in the Dired buffer and calling org-attach-dired-to-subtree or you can mark multiple files and call org-attach-dired-to-subtree to attach them all. The file or files get attached at the subtree the point is on in the Org buffer.