Please give me steps or idea in microwave design?.. 90km path length and 3 repeaters..thanks!!?

hello!!! I'm ECE student and we're required to have a project in our communication subject. It is about microwave design. I have no any idea about it, so please help!!. Our required path length is 90km with 3 repeaters. I'm trying it to google earth but I don't know how and where to start, which part in the philippines? Please give me a guide or steps in doing this said project?? Thanks a lot and GOD BLESS!!!!