Hello,
I would like to know how Suricata works, the basics, and what should be understood before starting its installation. Are there any clients for pfSense?
There is a customized GUI-administered Suricata package for the pfSense subsystem. You can install it from the SYSTEM > PACKAGE MANAGER menu within pfSense. The package is specific to pfSense and contains features not available in the generic upstream product which is entirely CLI (command-line interface) administered.
If you have questions about Suricata on pfSense, they should be directed to the dedicated subforum for the IDS/IPS packages available on pfSense located here: IDS/IPS | Netgate Forum.