Most sprite commands can be used by placing them on the very top of the screen. Some of them can be placed lower and have different effects, but they likely won't work if they read "MAY GLITCH!" You should put them in screen 0 if they do things like make layer 2 scroll up and down, but autoscrollers can work just fine wherever they are.
The game can only have so many different kinds of sprites in one level - there is a tileset dedicated to 'common' enemies like Koopas and Piranha Plants that is used in every level, but the rest of the enemies need to be loaded in with special tilesets. You can change those in
If your level has Layer 2 as a level instead of a background, you can click on that button to edit it. You can go into
and change if the level has layer 2 or not (Change "Layer 2: BG" into "Level." Changing "Layer 2 Interact" to yes
is a good idea)
Currently working on Æther: The Infinite Library
Other Submissions of mine:
SNES Controller Graphics (v2)