Finding the course creator is not intuitive. You need to go to Play Solo, then
over to Editor. Make a course with the elements there. If you need help in making a better hole, press
, then
for a tutorial video.
Once you've finished, you need to play the hole to validate it. Hit
then the center button for Test Mode. After you've validated it, press
, save it (far left button), then share it from the same menu.
This did not pop for me immediately. I had to go to the Main Menu and back into the Editor for it to register. If yours doesn't work, try quitting and going back in like I did.