have shapecrete already pressed down into a plastic lined bowl, level the top. Paint leaf and second bowl with oil and press down into the first bowl (maybe weight second bowl with water?) no instructions at click through but lots of ideas
Fill the balloon with water . This image illustrates why you don't completely fill the balloon you should always leave some room in the neck of the balloon, then as the form dries the pressure has somewhere to go and your clay wont split.