I have never used Lightroom before and thought i would give it a chance with the new redesign.
When I import my existing photos from my PC, Lightroom copies them into its own folder instead of just creating a link to the original image file. Of course I have not enough storage to duplicate all my hundreds of gigabytes of photos just to view them in Lightroom.
Is there a way of viewing and editing images without duplicating and keep all my image files in their original location?
Lr CC copies your images to get the originals backed-up in the cloud. Think of this as temporary storage. They eventually drop out of the system cache (unless actively being worked on) to be replaced by much smaller proxies. This is how Lr CC efficiently manages disk space on computers and mobile devices.
Thanks for your answer, do I understand it correctly that the duplicated files are temporary "working copies" and will be deleted after they have been uploaded to the cloud and after reaching the storage limit percentage specified in the settings?
Basically yes. You should end up with quite a reasonable size cache in relation to the real size of files stored in the cloud.