This repository is undergoing a major overhaul. It will soon be a monorepo with installable packages like you're used to, with the option to "eject" when you want full control over the internals.
Until then, if you're curious about what kind of code is generated by the Molecule Assembler, you can check out the mlcl-9239f003850cf8b8c8bdc881b5c2e93853b6fb58 branch.
To get started assembling your own fully functional, full-stack, cross-platform applications, visit assemble.molecule.dev.
Also see the Molecule.dev CLI, mlcl.