Hi,
Here is an example of snmpv3 on ASA:-
snmp-server group SNMPGRP v3 priv
snmp-server user SNMPUSER SNMPGRP v3 encrypted auth md5 StrongPassword priv aes 128 AnotherStrongPassword
snmp-server host mgmt 192.168.10.5 version 3 SNMPUSER
When it comes to adding to Solarwinds you would need to ensure you select the correct algorithms as specified in the configuration (md5/aes128 or whatever you select). Use a strong password where indicated.
HTH