This is a GPS/radio tracker for high altitude balloons. It uses a GPS receiver to determine its position, and a LoRa transceiver to transmit that position to the ground. It is written in C for the Pi Pico microcontroller, using the official C/C++ SDK. The resulting executable code can be downloaded to the Pico using a serial programming/debug cable as described in the Pico C/C++ SDK manual. You will need a means of receiving the telemetry from your tracker. One popular option is the Pi LoRa HAB gateway.