If you have a friend who can help that's better. In fact thinking about this more, although it's a product targeted towards Apple iPad users, it's not an actual Apple product, so it may be more appropriate if the discussion was pursued on a more relevant forum?
http://www.hackseagatesatellite.com/privateforum/
The admins there actually modify some of the Linux scripts running on the GFS, & package it all together for installation. I haven't bought their package but they seem to have several satisfied Customers, so that may be your best route. It's non-trivial to guide people without a fair amount of experience already, & unlike myself, these folk are always available to answer questions. At the very least you can register on their forum & read posts to see if it looks like what you need.
I'm currently experimenting with an alternative to the FTP server, as we need to locally backup Pages & Numbers files. We can't rely on Internet access all the time, & the GFS is a good device to backup to. It works for photos too, but isn't happy receiving large video files from iPad. Nothing needs to be installed, as one just needs to enable software on the GFS that isn't currently enabled. I'm unsure if video backup is practical because of the way the software works, so am leaving the FTP server on anyway as that's reliable for large files, but it's no good for Pages & Numbers which must use WebDAV.
Another useful external resource is Seagate's own forum for the GFS, but does seem to have a bias from unhappy users. Although GFS currently has some limitations, Seagate engineer(s?) are working on improvements, & compared to some other products posted about here, has far greater capacity, & seems a good piece of hardware to me.
HTH.
