Adding a Second External Drive

Ok, so I ran out of room on my External Drive (WD 1TB), bought a 2nd drive (WD 2TB). I was told I could just hook up a powered USB Hub and plug them both in and it would work. Well, I can see my original drive but not the new one. I’m using Cyberduck for my FTP transfer program. Any help would be appreciated.

Do you know the format of thew new drive? The AppleTV will support drives formatted in Mac OS and FAT32 format.