2005 Ford freestyle possibily needs something??? HELP?!!

Hi, I don’t know much about vehicles, but I
know a little but about three months ago I left
my car, running for maybe five minutes to lock
my door and grab my purse and when I came
out, there’s a little bit of smoke, but not much to
where it looks like it was overheating and
instead of fluid leaking from the bottom of my
engine, it was like splurged out of the front of
my car maybe about two or 3 feet in front of it
on the sidewalk it had no color or smell really.
So I checked my fluid levels and my engine was
completely dry so I filled it up with about 3
gallons of water or more. My check engine light
has been on, but I think it was before this
problem. Also, I think my alternator may be
going bad because when I have my car running
and I unhook my battery, it stops running