Baking Normal/Specularity onto Diffuse

Hey Guys,

I recently started learning to texture but through PBR so I’ve not had to deal with highlighting and all that jazz. Though, now that I’ve moved onto texturing for a program/game that used diffuse, specularity and normal (Sometimes only allowing a diffuse alone); I thus need to properly do highlighting onto the diffuse texture.

I’ve already made the diffuse texture without highlighting through substance designer/painter, along with the specularity and the normal map. Is it possible for anyone to explain (In fairly layman’s terms, as I’ve only ever used blender to bake Ambient Occlusion maps and to actually model) how I would go about putting these maps into blender and baking the lighting that I would normally see from the normal/specular onto the diffuse.

I’ve had a look multiple times on youtube for an explanation, searching what I would assume is required on google and messing about in Blender but I’ve still got nothing.