Take a look at these articles, they can help you do port forwarding (look specifically at the DNAT).
https://kb.juniper.net/library/CUSTOMERSERVICE/technotes/Junos_NAT_Examples.pdf
https://www.fir3net.com/Firewalls/Juniper/juniper-srx-destination-nat-port-forwarding.html
>show log messages
Specifically what would you want to find out about the internet outages?
Finally Juniper devices is getting some play! Too bad they techs are not being trained.