Mini tutorial for DSA network config

Installing and Using OpenWrt Network and Wireless Configuration
83

Hello! But how to make something like this How can I change my router's lan port to wan port? - #4 by lleachii with new syntax with DSA? I'm a newbie in DSA and can't understand how it need to be with new syntax.

On old syntax I has

config switch
	option name 'switch0'
	option reset '1'
	option enable_vlan '1'

config switch_vlan
	option device 'switch0'
	option vlan '1'
	option vid '1'
	option ports '6t 0 1 2'

config switch_vlan
	option device 'switch0'
	option vlan '2'
	option vid '2'
	option ports '6t 4'

config switch_vlan
	option device 'switch0'
	option vlan '3'
	option vid '3'
	option ports '6t 3'

config interface 'wanb'
	option ifname 'eth0.3'
	option _orig_ifname 'eth0.3'
	option _orig_bridge 'false'

but with new syntax I don't know how to make this thing.