You can use cmake (3.13 or later) to build the development environment for your platform. You will also need the Vulkan SDK, git, and python 3 installed.
To compile the project you will run cmake -D CMAKE_BUILD_TYPE=Release -H. -Bbuild followed by cmake --build build. The binary will be in the build directory, along with a resources folder. You can customize the blocks, renderers, terrain generation, etc. by modifying the resources in those folders. Shaders should be in their glsl forms with an appropriate file extension (.frag, .vert, etc.) and will be compiled automatically when you run the program.
If you're debugging a custom renderer, it is recommended to use RenderDoc to help visualize what's going on.
All of the program's content is dynamically loaded through lua files inside the resources folder next to the vecs binary. Documentation on these files will be coming at a later time, but for now you can use the default resources files as a reference.