Use command snmpconf to create a snmpd.conf file in the current directory:
- Read none existing file.
- Choose to setup the snmpd.conf.
- Choose to setup the Access Control.
- Choose to setup a SNMPv1/SNMPv2c read-only access community name.
- community name: public
- network address to accept: localhost
- restricted OID [RETURN for no-restriction]:
- finished, finished, quit
Review and copy the created snmpd.conf file into /usr/local/etc/snmpd/snmpd.conf or somewhere else where it will be found (e.g. /etc/snmpd.conf, it depends on compile-time options).
You should also read the snmpd.conf manual as well.