help for project ultrasonic wind sensor

hello my friends...
i have a final project which is hard for me. i have done some part of this project but i can't understand a little part.
i use ultrasonic transducers for find direction and speed of wind. i have 4 sensors and i connect them analog multplexer. i think that i can measure the wind speed and direction by measuring the time the sound wave takes between two sensor. but i can't find how can i use pic and how can i connect this system. i have some examples but they are not clear.
if you have, can you send me some circuit examples or can you explain how i can do it. i am rookie and i need your help...

is there nobody to help!!!

To help you we neeed a place to start.

Post the schematic of the example that is the best match to what you want to build and ask questions that will help you understand it.

Also tell us what you know and do not know. Can you proigram a PIC and if so in what language(s).