VLAN for WiFi with DHCP

This is really basic, I am sure. Normally I would try to figure it out on my own but do not have the luxury of time.

I have an SRX300 with no specified VLAN's, just the default:

root@HSRX300# run show vlans

Routing instance        VLAN name       Tag        Interfaces
default-switch                 default                 1

I would like a VLAN for guest WiFI and have the SRX also server a DHCP range to this VLAN as well.

I've seen a few examples but each seem to not quite apply or have a few mistakes in the examples that must later be corrected, etc.

Thanks in advance.