Reference see the following for details, making and running C programs.
 
https://datasheets.raspberrypi.com/picow/connecting-to-the-internet-with-pico-w.pdf

Each folder contains the following type of files. The UF2 file is a ready to run compiled program. See above PDF file for how to run it or build a new version.

CMakeLists.txt
pico_sdk_import.cmake
whets.c
whets.uf2

The C file identifies  the procedure used to compile

mkdir build
cd build
export PICO_SDK_PATH=../../pico-sdk
cmake ..
make
minicom -b 115200 -o -D /dev/serial0

On installing to run, results appear in minicom

