It's supposed to be easy...
Put Exiftool(-k).exe into any folder and make Desktop shortcut from it (right-click on Exiftool(-k).exe, select menu "Send To">Desktop).
Now move image file (not shortcut of image file or similar) onto Exiftool(-k) icon on your Desktop. After you do that, a (black) window will appear, containing metadata of image file.
Important is, you drag image file (e.g. from any folder in Windows Explorer) -not a shortcut or file containing a link to image file (which might be the case if you drag from browser). That is, you should download image first.
No, for using Exiftool, you don't need Photoshop (or anything else).