It is quite simple actually
ras> sys logs load
ras> sys logs syslog display
ras> sys logs syslog display
Active:Â No
Syslog IP Address:Â 0.0.0.0
Log Facility:Â Local 1
ras> sys logs syslog active 1
ras> sys logs syslog server 192.168.1.2
ras> sys logs save
ras> sys logs syslog display
Active:Â Yes
Syslog IP Address:Â 192.168.1.2
Log Facility:Â Local 1