Firewall Log collection using Postman

Essentially this is not possible from a Central perspective. The Logs in the Datalake are stored there and cannot be extracted. 

But you can send Data from your firewalls directly to a SIEM. 

Can you provide more details about how to send data from the firewall directly to the SIEM application?

The following document explains the configuration steps you'll need to follow to send data to a Syslog server.
- Add a syslog server

The following document explains the configuration steps you'll need to follow to send data to a Syslog server.
- Add a syslog server