Logic Pro - Point to External Drive - Sound Library

I have my sound library on an external drive. I cannot figure out a simple way to tell Logic Pro to point to the external drive where my sound library is. I've tried "relocate" (which is not really what I want to do - I don't care about the sound library installed on my external drive - it's just the basics) and you can see from the screen pic that Logic sees sound library files on the external but it is "greyed out" and I am unable to select that external drive for some reason. Please advise... how do I point to an existing song library on an external drive? Thanks!