How to copy files from one external into another?

Hey guys, I am in the process of copying over my music folders from one external drive to another external. Problem is when I open one drive [A] which already has a lot of music folders and I try to paste from the other drive [B] into drive A, I am not seeing an empty spot to Paste.

This means that the files I wish to copy over might be installed into any one of the folders already in drive A, what can I do here please?