ferrocement project usually starts with a Rebar frame. This one is extremely rigid, with a lot of short diagonals criss-crossing throughout the structure - all intersections are welded. Then, the skeleton is covered with mesh - in this case, expanded steel lath. It is wired in place, enough to keep it firm when you're applying the cement. Chicken wire is sometimes used, when there is some backing behind the surface to help the cement stick.