In the section defining firewall rules in the quick start guide there are some errors.
According to the guide this is how you set state established

set firewall ipv4 forward filter rule 10 state established 'enable'

But it will give you this error

Configuration path: firewall ipv4 input filter rule 10 state established [enable] is not valid
  Set failed

The correct syntax is to not include the 'enable' part

set firewall ipv4 input filter rule 10 state established

This syntax error is made multiple times in the quick start guide.