How to build custom level editor?

Hello, everyone.

I just start to play with Unreal Engine and I have a question about the easy way to build custom level editor.
So I worked with Unity3d before. For example, I can create a simple script for WindowEditor where I had a couple a variable x and z - and button. For example x = 8 and y = 8 after click button. Script created grid 8x8 on Scene.

So how I can create it something like that?

p.s Sorry for my bad English : )

Have you tried BP construction script ?

Thanks. I think this what I want : )