To make a flatland map change the acres A & F acres 0-6 as well as B, C, D, & E acres 0 & 6 to flat-0 where if any other beyond that are changed it will created glitched areas between the edge of the visible map to the ocean barrier that is meant to be the water tiles between the beach and perimeter fencing. This works with fish and critters without any extra work, but to get stacks of flower materials you need to place 10 of the flowers with flag0 set to 20, pick them up, drop them, extract the save, use NHSE to clone the 10 stack, and then one last time go in game and pick up each 10 stack and drop them again. To place an item as a dropped item change flag0 to 20. To place items as is leave flag0 as is or go up one number at a time to rotate the item if needed.

Use (item #5656) with the count changed to the number digits for the HEX associated with the item that you can find on one of the many item lists available. If you want to make 1x2, 2x1, 2x2, 3x3, 2x3, 3x2, etc tiles that do not connect to similar road pieces next to it then use the island designer tool in game to make the paths before saving and extracting so that you can make a legend/key of which tile needs to be what to connect to the correct adjacent squares while avoiding connecting to ones you do not want When you want to place roads that connect place the road piece 80A for whatever type of tile you choose. Shift+left click changes the tile to the terrain/item selected while alt+left click deletes it

I will share some tips on using the NHSE better It comes out much cleaner and you can arrange stuff the way you want while laying down paths correctly. Honestly I just laid them all out by hand.

Acnh save file download