For beginners, baking a normal map for a 3D model involves 4 key steps: create a high-poly (detailed) model, make a low-poly (simplified) version, align them (UV unwrap + position), and bake/export via software like Blender or Substance Painter.
High-poly adds details (e.g., wrinkles, scratches) that the low-poly (game/real-time ready) can’t hold. Aligning means unwrapping the low-poly’s UVs (so the map fits) and placing it exactly over the high-poly.
In software, set high-poly as "source" and low-poly as "target," pick tangent space (most common), and bake—this transfers high-poly details to the normal map.
If using Blender, go to Render > Bake > Normal, check "Selected to Active," and start with simple objects (e.g., beveled cube) to avoid artifacts like stretching.