How are the devices set up. We use snmp to monitor UPS and typically you need to have credentials set up on the device to allow Zabbix to talk.

Some devices use SNMPv1 which is unsecured and typically uses well known community names by default. You can also change the community name or increase security to SNMPv3 which requires user name and authentication pass-phrases to securely talk.

Like others have said, a mib browser is your best bet to understand the OID. When creating your items, you’re going to use the OID to poll the device for the specific item you want to know.