I don't know how to drag and drop sounds or images in the editor .-. I'm gonna have a bad time here if no one tells me how
um, you just drag and drop the file into the editor... if you want, you can also click on file > import and then you can just select the image or sound file to import.
If dragging it in isn't working for you, it may be because you're using some obscure format that your browser doesn't recognize as a picture or sound.
Thank you it worked!