Hi-
Right now, your $DISPLAY variabile is not set in your system. Can you please do step #4 here (copy+pasting a few commands into the terminal) and then open a new terminal to try again:
[
afni.nimh.nih.gov]
?
That should set up your terminal $DISPLAY variable. Note that Step #3 there describes how to set up easier copy+paste capability on the Windows Subsystem Linux. Note also Step #2 that describes how to set up your X server each time you open the Linux environment (which is necessary, as well).
-pt
