Enabled SSH Login on your VCenter Appliance ( this can be done through the GUI or via Direct Console Access )

Run the below commands replacing username and snmp servername

Source code

snmp.set --users username/-/-/none
snmp.set --communities liability
snmp.set --v3targets snmpservername@161/username/none/trap

This command will show you all the current settings

Source code

snmp.get