You'll come to an unmarked and unpaved "road" that you'll turn onto in the direction of the ocean. You'll drive for awhile, through kind of a farm and fields along the very passable road. You'll pay a man a small fee to park and then trek down the hill to the beach where you'll take a right.
We'll be somewhere near the strange structures and give better indications that day.
I'll potentially cross-list this event with another group in SF. Let's see if we can't make this a giant party. Everybody can bring along some beach-shareable snacks or beverages. The host will try to have some cups, but it's carry in, carry out (or your empty can if you drank it). Please be considerate and cleanup after yourselves!
It's generally too cold to swim.