Back to Artica SIEM for FortiGate
The Artica 4.50 ISO installs Debian 13 and Artica in one pass. When the setup wizard asks what the server is for, choose SIEM: it then downloads ClickHouse and starts the SIEM service on its own, so the appliance is ready to receive FortiGate logs when the wizard ends.
Download the Artica 4.50 image for Debian 13 (amd64):
artica-full-4.50.000000.debian13-amd64.dvd.iso
Boot the virtual machine or the physical server from the ISO and complete the installer. When it finishes, open the Artica console in a browser at https://<appliance address>:9000. The setup wizard starts.
The wizard has five steps:

If the ClickHouse download fails (no Internet access, for example), the rest of the wizard still completes. You can then install the two components by hand as described in Install Artica SIEM.
After the wizard, the left menu shows Statistics/SIEM. On the appliance, /usr/local/bin/artica-siem version prints the SIEM version.
Next: connect your FortiGate.