I think before you even consider any business you learn basic stuff like what fresnel distance means and how you calculate the equipment you need.
Although some people try to use normal WiFi equipment for solutions like this they are horrible and customers hate them. The main problem is there is no control of the end stations and they will transmit at the same time causing massive interference issues. This get worse and worse the more customers you add.
You need very specialized equipment from vendors that sell equipment to WISP providers. The newest equipment uses the same LTE protocols that cell providers use but on unlicensed radio bands.
This is not something you just throw together you have to really know what you are...