Note:Assumed L2 switch is a POe enabled switch.
I assume your default gateway is wireless controller and routing is done in controller
1.Assign ip address to controller
2.Create a wlan and map the ssid to the vlan.
Note:bridge mode "local" and bridge mode "tunnel" are two options.
3.map the required secuirty setting in the wlan. [wep,wpa2 etc]
4.Map the wlan to the radios.[wlan mapping]
This will get your wireless network up and running.
with static ip to clients.
now if needed you can use wireless controller as DHCP server or use and external dhcp server
for wireless clients
Gui is the easiest way to configure the controller.
Once the above steps are followed implemented and tested.
Add acl in controller to block specific subnets so that wireless subnets can access only internet.
below is the syntax.reference guide and user guides are available.
http://extrcdn.extremenetworks.com/wp-content/uploads/2014/01/WM3000CLIReferenceGuide_5.2.pdf
deny ip [
|any|host ] [|any|host]
[log rule-precedence <1-5000>|rule-precedence <1-5000>]
{rule-description }
Hope this throws some light for your requirement.