The time has finally come! K.K. Slider is performing on your island. When you first log into the game the day after you reach 3-star island rating, you’ll be taken straight to the concert following Isabelle’s island-wide broadcast.
K.K. plays the song Welcome Horizons and it rolls into credits. The song is recognisable as the Animal Crossing: New Horizons theme song.
After the concert, you’ll be visited right away by Tom Nook. First off, he gives you a copy of Welcome Horizons which you’ll be able to play on a radio or record player. He also announces that K.K. will play on your island every Saturday evening.
Most importantly though, Nook gives you a new app called Island Designer! You’ll now be able to unlock terraforming! You’ll be able to construct and demolish cliffs, control water ways and add ponds, and even add paths and change terrain.
At first, you’ll only be able to place paths down with Island Designer, but with enough Nook Miles you can unlock more features at the Nookstop.