The Snapping Tool is an utility tool that comes with the toolkit. The Snapping Tool will help when setting up your scene. The tool can be found under Tools/Snapping Tool or press Ctrl+L (Command on Mac). You can find the source code under Assets/UltimateIsometricToolkit/SnappingTool. Although it is not recommend you may delete that folder and remove the tool from your project, the toolkit does not depend on it.
The tool will snap the current selection in the hierarchy window to the closest increment of that vector.
When enabled will snap all
Transform components in the current hierarchy window selection automatically.
When pressed will snap all
Transform components currently selected in the hierarchy window.