They are in the game and mostly found around the Great Fairy Fountains. When Link dies it’ll restore 5 hearts and bring him back to life.
The 4 Great Fairy Fountains can be found in various places threw out the game. The fairies will can be found around the pods that the Great Fairies are in.
You can also cook them in a meal and make a Fairy Tonic to give you more hearts. If you do make a Fairy Tonic keep in mind that if you die it will not bring you back to life so keep an eye on your hearts.
I hope this helps.
Also it’s not a problem. That’s what we’re here for! ^-^