Once you finish the process described on the PDF, you'll see a new button next to the "Add Temporary Attachment" button that says "Upload File" whenever you post on DBF.
I've made a screen recording on my phone, showing how to upload an image via your phone. Watch it here:
You'll notice that the first thing I do in that video is change my browser to Desktop. Iphone users will probably see a version of DBF that fits their phone perfectly. Galaxy users like me, end up with a zoomed out version.
Note: to see the button on your phone, you'll have to "request desktop version" (or whatever term your phone's internet browser calls it in the options for each page/tab) so you aren't stuck with the lame mobile version of DBF.
I just now updated the Cloudinary upload widget to a fix that is supposed to make the new version of Cloudinary's upload widget v.2.0 work. The old version that DBF and most other forums were/are running won't work after December 31, 2021, so hopefully this update fixes the issue.
Other than it taking 1 additional click (you now click DONE), and it looking a little different, it seems to be working perfectly fine.