Orange flower water is a kind of liquid that smells like the flowers from an orange tree. People use it in cooking to add a nice flavor and smell to the food. It's kind of like putting seasoning on your food to make it taste better, but instead of adding taste, it adds a nice smell that makes your food more yummy.
You only need to use a very small amount of orange flower water when you cook because it can be pretty strong. It's like when you put too much ketchup on your hotdog and it's too overpowering. Too much orange flower water can make your food taste too perfume-y.
So, in short, orange flower water is a special liquid that smells like orange flowers and is used to make food taste and smell better, but you have to be careful not to use too much!