Lets say I have the following security policies

set security policies from-zone CAMERAS to-zone INTERNET policy CAMERAS-to-INTERNET match source-address any
set security policies from-zone CAMERAS to-zone INTERNET policy CAMERAS-to-INTERNET match destination-address any
set security policies from-zone CAMERAS to-zone INTERNET policy CAMERAS-to-INTERNET match application any
set security policies from-zone CAMERAS to-zone INTERNET policy CAMERAS-to-INTERNET then deny

set security policies from-zone CAMERAS to-zone INTERNET policy CAMERAS-to-NTP match source-address any
set security policies from-zone CAMERAS to-zone INTERNET policy CAMERAS-to-NTP match destination-address any
set security policies from-zone CAMERAS to-zone INTERNET policy CAMERAS-to-NTP match application junos-ntp
set security policies from-zone CAMERAS to-zone INTERNET policy CAMERAS-to-NTP match application junos-dns-udp
set security policies from-zone CAMERAS to-zone INTERNET policy CAMERAS-to-NTP then permit

Now, I want the CAMERAS-to-NTP policy to be executed before the CAMERAS-to-INTERNET policy.

So I need to do the following:

insert security policies from-zone CAMERAS to-zone INTERNET policy CAMERAS-to-NTP before policy CAMERAS-to-INTERNET

And boom! we are done!