Oid Alert - how to do it properly

Good afternoon,

so I have this scenario, where i need to create an alert for custom OID graphs.
The graph is working correctly, as you can see in the picture.
I tried to create an alert using the OID (eg. 'oid' eq 2), and also, the correct OID name (eg. 'oid_name' eq 2). Both of them did not work.
Am I missing something important?
Please let me know how to create custom OID alert correctly.
Thanks

**Maybe the OID Name has to be set correctly in the Custom OID section, and later that name has to be used in the alerter?