G0/0/4⬇️{HW_3F_L2_SW_01:net.if.in[ifHCInOctets.8].last(0)}
G0 / 0/4 is the switch interface, HW_3F_L2_SW_01 (best written IP address, host name and sometimes unsuccessful) is a switch name: net.if.in [ifHCInOctets.8] is to build value switch .last (0) is the zabbix function
Configuration -> Host -> point to open the corresponding host -> monitored item, enter the monitored item, view the key monitoring interface.