snmpd - snmpv3 configuration

Hi evreyone

I want to configure snmpd for snmp v3

the config file is located in /etc/snmp.config

with the sample file i can get snmpv2 working

but when i change the sample file to support snmp v3 as suggested , the snmpd service won't start

if anyone can provide me a sample snmpd.config file which is working as snmp v3
I'll be be really thankfull

Note : I don't want to use net-snmp port