HeRALD, the Helium Roton Apparatus for Light Dark Matter, will use a superfluid helium target to study the sub-GeV dark matter parameter space. The HeRALD design is sensitive to all signal channels produced by nuclear recoils in superfluid helium: singlet and triplet excimers, as well as phonon and roton vibrational excitations. Excimers are detected via calorimetry in and around the superfluid helium. Vibrational excitations eject helium atoms from the superfluid-vacuum surface which are detected by adsorption onto calorimetry above the surface. I will discuss the design, sensitivity projections, and R&D for the HeRALD experiment.