You will be prompted to detatch the Joy-Con or connect additional controllers. (Players using the Labo Motorbike should select this option.) (Players using the Joy-Con Wheel should select this option.)
Have Player 1 adjust the race options as desired until you reach the character select screen.Highlight the appropriate number of players on the console (2P, 3P, or 4P) and press the A Button.Highlight Multiplayer on the game’s title menu.