When you start Applix, from the Athena menu or by typing add applix; applix & you can go to the graphics tool from the star menu. This program is slightly idiosyncratic, and it is meant for making slides, mostly, but it will serve in a pinch. The stroke button is what you use for freehand sketching. You can save the image as Jpeg, GIF, or PNG, among others.
Star Office, on the other hand, is much nicer to draw with, but then doesn't give you an easy way to save your work. That is where the PrintScreen button rushes to the rescue. Again, if no other tools are available, you can drraw a graphic in star office, hit PrintScreen, and later crop the screen dump with xv.