Hello again Ivet, your ipod_control folder is a hidden folder, if you want to see it select
tools->folder options and click the radio button "show hidden files and folders" under the view tab.
Yes you can drag and drop music onto your ipod and put it anywhere you want, that's the point with rockbox. Once you find your files in the ipod_control folder (amongst many other folders name F00 etc) you'll see that they're name ABD.mp3 etc.
I would recommend just deleting your ipod_control folder, (or just the ipod_control\music folder) transfering your songs by drag and drop, and then initializing your rockbox database.