Its simple like the Heartful Commune. You use cards/diamonds to interact with the fairies. It calls you roughly every 15 minutes for something but if you dont respond. Nothing happens, your selected fairy will say something and move on. It has mini games, very simple. More interaction, the more your fairy likes you/level up. There is outfits, food and accessories to mess with but they dont stay if you use thrm right away. You can store a few foods/things at a time. One of the few talking precure pets. Though limited to a few sayings (good night,good morning...etc) I would recommend buying "new" or complete, with pouch.
I have the Crystal Commune too. Removes the cards/diamonds and sound speech. Has a few mini games, simple. Adds a pedometer/motion sensor has all the characters in some way. You do more walking/adventure mode, the better. Longer trips will give you treasure each different. Can be used now/later. But generally the same care.