Open Python 3 using Menu > Programming > Python 3. This will cause a Python Shell window to appear. Select File > New File, and type in the following code:
from sense_hat import SenseHat
sense = SenseHat()
sense.show_message("Hello my name is Tim Peake")Select File > Save and choose a file name for your program, then select Run > Run module. Your message should then scroll across the LED matrix in white text.
Why not try changing the message between the double quotation marks and running your code again?