Making a main screen in Ursina

I am currently making a game with Ursina and i've been struggling to find a code to make a Main-Starting-Screen to start the game or show controlls.

Here is my game code:

game = Ursina()

ground = Entity(model = "untitled.blend", texture = "Soul Sand.jpg", scale = 400, collider = "mesh")

player = FirstPersonController(model = "player.blend", position = (-6.39844, 148.284, 62.5471),jump_height = 7, jump_duration = 0.5, speed = 10, texture = "Player Texture.jpg", collider = "mesh")
camera.z = None

health_bar = HealthBar(bar_color=color.lime.tint(-.25), roundness=.5, value=100)

def input(key):
    if key == "shift":
        player.speed = 25
    elif key == "control":
        player.speed = 10


house = Entity(model = "House.blend", texture = "Tree Texture.jpg", scale = 2, collider = "mesh", position = (0, 146.3, 15))

tree = Entity(model = "Tree.blend", scale = 15, texture = "Tree Texture.jpg", collider = "mesh", position = (15.5488, 140, 55.0674))

game.run()