Nexus 7, WD Passport 1tb, Stickmount, SupetSU

[Rich Vi]

Hello, I can link my WD Passport 1tb to my Nexus 7 using an external battery and otg cable. The Nexus Media Importer recognizes it. But I can not copy files from Nexus to the Passport. I searched and read that Stickmount can help. I've installed stick Stickmount but it's asking for SuperSU to be installed. I did that but I'm getting a message that there is no SU binary, and that I need to re-root. Can you help me as to what I should do next? Do I really need Stickmount for this? Is there any other way? Thanks!