Forward all traffic from wifi 2.4GHz to proxy server

I would like to forward all the traffic that my router is getting on his 2.4GHz wifi interface (or all wifi interface but not the ethX ports) to a proxy server.

I read some infos firewall conf here : firewall_configuration and squid conf here, the use of travelmate package here, and finally, tinyproxy here.

I didn't succeed yet so can you please get me some advice on how to do this ?