Found the path, and while it gives the basic layout, I think it is missing some detail. On that path the start and finish are not joined. Just make sure you import as the correct type.
Once you import go to the "Edit/switch active tracks" button, and copy your import multiple times. I suggest keeping the original as a clean copy, so turn it's visibility off. Select one of your copies, make it active, then switch to "Move node and control points" button, and start deleting nodes until that copy's length gets down to a manageable size (I suggest 1000m). Just keep stepping through the tracks deleting the appropriate nodes until you complete the loop.