FASER is a new experiment placed 480 meters downstream of the ATLAS interaction point at the LHC. FASER is designed to discover light and very weakly-interacting particles such as dark photons that are produced in the far-forward region of the LHC collisions. FASER would also directly detect collider neutrinos for the first time and study their properties at TeV energies, where no such measurements currently exist. The experiment has been successfully constructed and installed, already starting data acquisition since the beginning of LHC Run 3 in 2022. This talk will focus on the detector concept, design, commissioning including detector performance studies with the first collision data.