They were able to connect the school because the cabling they used, metal-packed armored cable (M-PAC), which is modeled on undersea cables, does not have to be in a protective duct. It is 4mm in diameter, light and flexible, so it can be installed by supervised volunteers or unskilled workers.
As shown below, a portion of the cable to the school is buried in a hand-dug ditch and another link is suspended overhead:
The cable used in this installation was supplied by OCC Corporation, but last June the International Telecommunication Union (ITU) adodpted a standard for "low-cost sustainable telecommunications infrastructure for rural communications in developing countries," L.1700.
As a framework standard, L.1700 is largely technology-neutral. Technology-specific best practices are provided by supplement texts such as ITU-T L Supplement 22, which specifies the design of a low-cost, terabit-capable optical cable that can be deployed on the ground’s surface with minimal expense and environmental impact. For more on the standard and it's intended application, check this post.
We have major fiber backbones in large cities -- might we also have do-it-yourself backbones in rural villages?