Even though the game doesn't come out until December 7th, I'm going ahead and making a thread.
Feel free to share and/or discuss any GTS related screencaps you've taken in this thread here. Some of these might also show up in the Super Smash Bros. Ultimate GTS screencap gallery at VGGTS World.
The instructions for capturing screenshots should be very simple given that most Switch controllers have a dedicated Capture button, and it's easy to copy these screenshots to a microSD card.