This document provides an overview of LoRaWAN technology. It discusses the benefits of LoRa including long range, low power consumption and bandwidth. It describes the key components of LoRaWAN including the physical layer, data link layer, and device classes. Common LoRaWAN topologies involving devices, gateways and network servers are shown. The document also introduces The Things Network, an open source initiative to build a decentralized IoT network, and provides guidance on developing IoT devices and gateways using Arm Mbed OS.