How to change the Grid(Environment) for prefab

[djnjbjb]

If I create a prefab from only a part of the tilemap, there will be a Grid(Environment) for the prefab.
But the Grid(Environment) is different from my need. For my project, the cell size is 0.32x0.32, but the Grid(Environment) is always 1x1.

There is nothing wrong using this prefab, because the Grid in scene is 0.32x0.32, and the prefab follows the rule.
But if the prefab is viewed, it is ugly. The cell size should be 0.32x0.32 but it is viewd as 1x1, everything is far from each other.

So, how can I change the Grid(Environment) for prefab. Specificlally, I want to change the cell size.