The best way to node a shader for a 3D model is to start with basic attributes (e.g., base color, roughness), build connections step-by-step, and preview changes in the viewport.
Use an incremental approach—add texture maps (like normal or ambient occlusion) one at a time, blend properties with simple math nodes (mix, multiply), and test how each node affects the look to match the model’s intended style (realistic or stylized).
For beginners, starting with a PBR (Physically Based Rendering) shader in tools like Blender is a low-threshold step—it’s widely supported and easier to iterate on.