https://help.ui.com/hc/en-us/articles/204960094-EdgeRouter-Configuration-and-Operational-Mode#:~:text=If%20you%20wish%20to%20run,Mode%2C%20use%20the%20run%20command.
If you wish to run an Operational Mode command from while in Configuration Mode, use the run command.
https://www.juniper.net/documentation/en_US/src4.10/topics/task/operational/cli-modes-switching.html

if term has no "then" configured, matched packets are accepted by default
https://www.juniper.net/documentation/us/en/software/junos/routing-policy/topics/concept/firewall-filter-ex-series-evaluation-understanding.html Additionaly:
if term has no "from" configured, every packet is matched to term
if packet does not match any term - default term (implicit discard) is used

The configure private command allows multiple users to edit different parts of a configuration at the same time and commit only their changes or roll back, without interfering with each other's changes. When the configure private command is used, you work in a private candidate configuration, which is a copy of the most recently committed configuration.
https://kb.juniper.net/InfoCenter/index?page=content&id=KB19653&actp=METADATA