Custom editor mode - need help

Hi, Community!

We are trying to develop a Custom Editor Mode, which is similar to the Landscape Editor Mode. We need more of a 3D tile map, placing different cube mesh (Instanced Static Mesh) in the environment and snapping to the grid. We should be able to select between terrain cube types (Ground , Grass , Sand etc).

There are a few examples available for Scriptable tools which is close enough, but nothing related to making a Custom Editor Mode in C++.

Does anybody have experience developing something like this? If so, can you please share it? Or maybe the guides or docs that you know of explaining this area of the engine? I would really appreciate it and promise a Steam code for the game we are currently developing:)