  Discrete time crystals are a many-body state of matter where the extensive
system's dynamics are slower than the forces acting on it. Nowadays, there is a
growing debate regarding the specific properties required to demonstrate such a
many-body state, alongside several experimental realizations. In this work, we
provide a simple and pedagogical framework by which to obtain many-body time
crystals using parametrically coupled resonators. In our analysis, we use
classical period-doubling bifurcation theory and present a clear distinction
between single-mode time-translation symmetry breaking and a situation where an
extensive number of degrees of freedom undergo the transition. We
experimentally demonstrate this paradigm using coupled mechanical oscillators,
thus providing a clear route for time crystals realizations in real materials.
