Welcome to the forum! I am glad you are trying SMBX. It is really fun, yet has a bunch of things to learn before starting. Like you can use paint or Photoshop to make custom graphics, or use layers and events to do things that you would see in actual Mario games, how to use blocks, backgrounds, and npcs, and using recolors to prevent style mixing or clash. Custom graphics and style mixing is not needed, but I want you to use block types and items more wiser, and not just randomly placed. It definitely takes a long time to make projects and get use to SMBX It took me 3 years just to get the hang of it. I would suggest taking some time looking up tutorials on YouTube. Good luck on the project! I will be back when it's finished!