
Hi Tarek, yes that is what 'backup' does when you click it. The problem now is how much space do you have on you C Drive? If you download your files from OneDrive (cloud) to your device. They will take up room on your C Drive. Would you have enough room on your C Drive to copy the files onto C Drive.
If you go to>This PC\C:\Users\UserName you will see all the files on your C: Drive. One of those files is the Blue OneDrive Folder. All the files in there are on OneDrive. All the rest of the files are on C: Drive. You can create a Manila Folder on C: Drive. Right click>Create>folder.
You can open the Blue OneDrive Folder (double click it). You can copy the files that have been downloaded (always keep on this device) to the new Manila Folder. NOTE you can only do this if you have enough room. You can of course do this bit by bit, that is when you have copied a file/s to the Manila Folder>In OneDrive Folder>Right click on the file and chose>Free up space. This move the file to OneDrive online, to free up space on C Drive.