I have two classic amigas with wifi.
It was easy with Genesis.
1. Genesis doesn't have working DHCP client. So you need to play with static IPs, set them manually.
2. Make it work without encryption first. Just copy PRISM2.device to DEVS folder in your system partition.
With genesis you just need to select prism2.device and set static ip/dns. It will automatically connect first unencrypted wifi, without any other settings, IF you configured it right. If Genesis tells you that you are connected, but can't surf net, you IP/DNS setting are wrong.
PS. Use your phone internet sharing, turn of encryption, so that you don't need to turn of encryption of your home lan. Check what IP your phone gives to your PC and use then as a example.
3. When it works run PRISM2 installer, it will set WPA, ask some questions like SSID and sharedkey. Then change IP and DNS settings with Genesis prefs so that they are right to your LAN
4. Consider to buying Roadshow
http://roadshow.apc-tcp.de/index-de.php