How to setup private network (maybe mesh) in a Latin America elementary/middle/high school?

I want to do this for a school in Peru, but was hoping for some guidance on hardware and software. I want to make a private portal and include chat between teachers and student/parent. Any other ideas would be much helpful. Here is our website: https://www.jgmproject.com/

The DREAM: Since many of the kids are taking classes from school it needs to be accessible to users at about 1-3 kilometer distance from the school.