[Herefordshire] Newbie Question: File Server

[Ben Stephens]

I was wondering if anyone could give me some advice about setting up a
fairly basic fileserver for a network with about 2 windows pcs on it.
What hardware/software.

Would backing up to a USB hard disk be a good idea?

I was thinking about maybe a dell value server (they've got a discount
on at the mo) or building something myself but i'm not really sure
what I need / what works best with linux.

Or possibly something a little more exotic like a mac mini or a
mini-itx system but it would probably be best to steer clear of
something like that if it's likely to get complicated.

I'm not really sure what a file server is supposed to do either,
except keep a backup, which we could maybe do with a usb hard disk
anyway.

Thanks, Ben