To find out what your Ktorrent is doing in time:
-Click Download Tab beside Seeding tab.
-Highlight and examine data/informations found along the line or row
-There you can find what Ktorrent is currently doing: if it is downloading it will say so and show you the percentage of the file downloaded; if not it will say that download is "stalled" and the running percentage is "halted" or not running. If download is done you will see that the download is 100% and in fact the file is automatically moved to "Seeding" no longer in the "Downloads" tab.
-Check also the "chunks" if all 100% are completed, this you can find by clicking the "File" tab located at the bottom of the Ktorrent interface.
Finally, computing, in anything you do always use your common sense and get familiar with the software. Don't be afraid to try anything, Linux is stable and if it breaks... it is not a crime.
Hope this helps. Goodluck.