You can create a new catalog which will be empty File->New Catalog. There is no SAVE command in Lightroom, so in general you don't need to SAVE your photos. If you have done some editing of the photos, and you want that to show up in the new catalog, select the photos and then Ctrl/Cmd-S to save the metadata with the photos.
If all your photos are "in a mess" (whatever that means), you might consider learning how to organize in Lightroom by getting rid of that mess using Lightroom methods. But generally, if you are beginning and your photos are all "in a mess", then creating a new catalog and importing again will result in the same mess. You would need to identify what you did wrong, and fix that.