I wouldn't be able to explain how to arrange it myself since I don't do pixel art and my brain would just waffle a bit at the attempt lol. FlowPoly on youtube has a tutorial for making rpgmaker tilesets in aseprite, so maybe that will help? But I recommend looking at tilesets that are already set up for rpgmaker. They're separated into sections titled A1, A2, B, etc. Clockwork Raven has a great free tileset called Green Forest that is set up for rpgmaker, so you could go study that. or maybe even ask Clockwork Raven for advice?
I would definitely suggest adding a version of your tilesets that's formatted for rpgmaker if you're going to attach the tag for the engine to them, since most people who are buying tilesets for rpgmaker will want them to already be set up for use in the engine.
Good luck!