Game Development – A literal sandbox in Unity3D

I’m new to Unity (and game development in general) and I’ve been trying to figure out how to make sand that will be affected by a gameobject. For instance, I’m trying to create a zen garden of sorts in the game where you can pull out various rakes and walk along the sand to make designs. I’ve done tons of searching but haven’t quite been able to figure out where to start. I don’t know if it’d be better to try and make it happen with heightmaps or a deformation mesh. I want the sand to ONLY be affected by the rake(s) when in use and not by the footprints of the character.

This may be a dumb question to ask so excuse my ignorance if so. No code provided because, well, I don’t even know where to begin to achieve what I’m after (the only thing I’ve been able to find has been based on particle systems which I don’t think is what I’m looking for). Any guidance would be huge for me because I’m feeling pretty low IQ right now