How can 2 LANs communicate/exchange traffic inside FortiGate ?

[MAIKO]

Hi I'm struggling trying to communicate from 2 different LANs inside fortigate , what can I do ? 

 I want to ping PC3 from PC1 and vice-versa or the internet (8.8.8.8) from any PC but I can't

I can ping all the PCs and the Internet from FortiGate CLI tho, I think I read I should do routing policy but Idk how to do that exactly 

[abarushka]

Hello,

You may consider to collect traffic sniffer "diagnose sniffer packet any 'host 10.20.10.11 and host 10.20.20.13' 4 0 a" and debug flow while pinging:

diagnose debug flow filter saddr 10.20.10.11
diagnose debug flow filter daddr 10.20.20.13
diagnose debug flow show function-name enable
diagnose debug flow trace start 10
diagnose debug enable

[MAIKO]

So I apparently I did it , just added 6 firewall policies 

is there a guide that shows all different CLI commands please ? and isn't there a better way to do what I just did ?

[abarushka]

Hello,

Traffic should be explicitly allowed, otherwise it will be dropped. In the debug flow firewall policy lookup process is shown.