I'm trying to write a text-based game using turtle, and I'm having trouble making the text fade off after appearing for a few seconds

I'm trying to make the text appear for a few second, and then go to the next text without overlaying it.When I use the clear function, it makes the text not appear in the first place..

import turtle

#The screen
wn = turtle.Screen()
wn.setup(width=800,height=500)
wn.bgcolor("white")
wn.title("Asgard")

#The text
pn = turtle.Turtle()
pn.color("black")
pn.hideturtle()
pn.write("Welcom To Asgard ",align='center',font=("arial",16,'normal'))