Components

Component	What it does
Pathtracer	The renderer: renders the PT GEOs, PT LIGHTs and POPs beside it through a camera, and denoises the image.
PT GEO	Places a POP in the scene, moves it like a Geometry COMP, and gives it a material.
PT MAT	A physically based material: colour, metal, roughness, glass, clear coat, emission and textures.
PT LIGHT	An area light: a rectangle, circle, ring or point, or any shape you wire in.

A scene needs one Pathtracer and a Camera COMP. Everything else is optional: geometry can be plain POPs, lights can be emitting materials, and the HDRI map can light the whole scene alone.