A perfect snowman in ACNH requires a specific amount of snowballs to be created and placed in the correct order. The first snowball must be placed in the middle, the second snowball on top of the first, and the third snowball on top of the second, forming a snowman. The player must also be in possession of a shovel and have the snowman icon in their inventory. Additionally, the player must have a certain number of snowflakes to create the snowballs.