I take no credit for this but it was/is a fun project especially if you live in rural areas or if your in the city and want to pick up a buddy's WiFi
Between the instructions on these 2 sites you should be able to build a functional dish antenna:
https://www.ab9il.net/wlan-projects/wifi3.html
https://www.engadget.com/2005/11/15/how-to-build-a-wifi-biquad-dish-antenna/