They  communicate first through an exchange of mathematical concepts, like the value of pi, and then through answers to specific questions about Martian life. The transmissions claim that Mars is a utopia, which has led to great technological advancement and the elimination of scarcity, but that there is no fear of nuclear war.
They start by sharing mathematical ideas, such as pi's significance, and eventually address specific queries about Martian life. The signals indicate a utopian Mars with advanced technology and the absence of scarcity, but without the threat of nuclear war.