SDK compatibility: 13
SoftDevice compatibility: s332 4.0.2

Place the ble_ant_app_hrm folder under the examples/multiprotocol folder of your nRF5 SDK installation
The project file to open (Keil v5) is
examples/multiprotocol/ble_ant_app_hrm/d52_starterkit/s332/arm5_no_packs/ble_ant_app_hrm_s332.uvprojx