The Muon IDentifier detector (MID) is a subsystem proposed for the upgrade of ALICE at CERN. The ALICE 3 project is programmed as the next-generation heavy-ion experiment at the LHC, to be operated during the LHC runs 5 and 6. The baseline option for MID is plastic scintillator bars equipped with wavelength shifting fiber and silicon photomultipliers for readout. In order to verify the hadron rejection factor at the level of 3%, a small prototype was built consisting of an absorber 70 cm thick, and a muon chamber consisting of 10 plastic scintillation bars. In this presentation I will talk about the simulation of the prototype, its construction, and the first results using atmospheric muons as well as preliminary results obtained at the T10 test beam facility at CERN.