What is the function of the beamforming process in the simulink example 'FMCW Radar Range, Speed, and Angle Estimation of Multiple Targets'?

Hi I am studying the modeling of FMCW radar in the Simulink and I found an example from the website https://www.mathworks.com/help/phased/examples/automotive-adaptive-cruise-control-using-fmcw-and-mfsk-technology.html. I am not sure why in the last example that the range-doppler responese output should be processed using sum-and-delay beamforming which separately spans with azimuth angle -0.5, 0, 0.5 degrees. Could someone answer this question for me?