I heard people complaining that Lightroom CC doesn't store the files only on cloud and it also stores the files on the local drive, no matter what you choose in the settings.
One of our friends from this forum, said that he doesn't want to store the files on the local drive, he wants to use this option by storing the files on the cloud and saving space on his local drive and no matter what he did in the settings, Lightroom didn't remove the files from the local drive even after all the files were uploaded on the cloud.
Well, as I've seen, here's how the things are with Lightroom:
Step 1: Go to Preferences -> Local Storage and uncheck the box for Store a copy of ALL originals locally. You can also decrease the Target Available Disk Space Usage to 0%.
Step 2: When you add pictures to Lightroom, it copy them into its default location and you can see that location by going to Preferences -> Local Storage -> Your Lightroom CC Files. Click on Your Lightroom CC Files (see the above image) and it will open the folder where it stores your files on the local drive. I don't know if everybody has the same folder name, but mine is called 69f70ee2d07b491ab39609da78b36a4b/originals/ . There you'll find all the files that you added to Lightroom. Keep in mind, Lightroom doesn't move your files to that folder, it just copy them. From there, the files will be uploaded to your online storage.
And here's the point: when Lightroom finishes uploading your files on the online storage, it won't automatically delete the files from the local drive.
Step 3: After all the files were uploaded to your online storage, then you can delete the files from your local drive where Lightroom stores them by going to Preferences -> Local Storage -> Your Lightroom CC Files ->->-> 69f70ee2d07b491ab39609da78b36a4b/originals/ .
After this step, you can work with your files directly from online storage and any modification that you make to your files, it will also be stored on your online storage.
The bad thing, but I guess this will be fixed soon, is that every time when you add new pictures to Lightroom, you'll have to repeat the steps above to free your local storage. Lightroom won't automatically delete the files from the local storage. This happens only when you use the desktop version of Lightroom CC and you add pictures from your computer. All the pictures added from your mobile through your Lightroom CC mobile app, will be saved on your online storage and not downloaded on your computer unless you check the option Store a copy of ALL originals locally by going to Preferences -> Local Storage from your desktop version of Lightroom CC.
If you want to download just one or few pictures from the online storage and not to download all of them, just go to Lightroom and choose a picture, right click on it and choose Save To... This option will allow you to choose a destination on your local drive where you want to save the picture and how you want to save it, in JPG format, or in the original format + all the settings that you made to it.
I hope this helped
I've tested the steps from above. If I said something wrong, please replay.