A Raymarcher I wrote following a blend of several tutorials (below) and my own work. It runs on the cpu so it's quite slow.
https://raytracing.github.io/books/RayTracingInOneWeekend.html#overview
http://jamie-wong.com/2016/07/15/ray-marching-signed-distance-functions/
https://iquilezles.org/articles/distfunctions/
Clone the repo and run make in the src folder to get the executable, ./main. Running ./main will output .ppm files in the ../output/ directory, which can be assembled into a video via your own methods or via the ./render.sh script (requires ffmpeg).