The COHERENT collaboration measured coherent elastic neutrino-nucleus scattering (CEvNS) for the first time at the Spallation Neutron Source at Oak Ridge National Laboratory, using a CsI[Na] detector [1]. Here we discuss the nature of the CEvNS process, physics motivations, and experimental considerations for measuring CEvNS. We describe the CsI[Na] measurement, along with status and future of COHERENT.