do a google of "solar stills". there is lots of info out there.

however, it might be noted that even the US Armed Forced stopped having those
things made IIRC more than a decade ago. Hard to use, hard to keep from
tearing the things and they only made a tiny amount of water. I owe two of
them I picked up cheap.

I am concerned with reclaiming sea water for drinking water for emergency
situations on a boat. I saw a TV show a while back where they had a tripod
with a plastic cover over it, sort of like a teepee with buckets at the
bottom ends of the tripod legs, and a bucket in the center. They put
seawater in the center bucket, the sea water would evaporate leaving the
salt in the bucket, the sides of the tripod would condensate with water and
drip down the sides to the leg buckets for drinking. Does anyone know where
to buy this or does anyone have a description on how to make one?