See https://docs.crowdsec.net/docs/next/getting_started/install_crowdsec_pfsense
or you can test this installation script:
# fetch https://raw.githubusercontent.com/crowdsecurity/pfSense-pkg-crowdsec/refs/heads/main/install-crowdsec.sh
# sh install-crowdsec.sh --release v0.1.4-1.6.3_2
Without a --release option, the script will install the latest stable (i.e non pre-release) version.