DIY Homeowner's Kit/Course for Minor Foundation Void Repair

A homeowner has discovered a hole under their foundation and is unsure whether it's a DIY fix or requires a professional, and what materials to use (cement, foam, etc.). This indicates a need for an accessible information resource (e.g., an online course or detailed guide) or a specific product kit that provides clear instructions, appropriate materials, and tools for homeowners to safely and effectively address minor, non-structural voids or holes under slab foundations. The kit or course should clarify diagnostic steps, material selection, and application techniques to prevent further issues.