Choose a sensible first crop, understand the four things roots need and build confidence without unnecessary kit.
Start with a small Kratky jar or a compact deep-water-culture kit and grow lettuce or basil. These forgiving combinations teach water level, nutrient mixing and light placement without adding plumbing.
Hydroponics replaces soil with a managed root zone. Water carries dissolved mineral nutrients; roots also need oxygen, a suitable pH and enough light above the plant.
A bright, washable spot with ventilation is more useful than a fashionable cabinet. Kitchens suit herbs; utility rooms suit larger reservoirs; living rooms need quiet pumps and careful spill control.
A clear-sided Kratky jar containing lettuce is the simplest demonstration because the roots are visible and there is no mains-powered pump. An adult should handle nutrients, pH adjusters and any electrical equipment.