How Texture Paint is working?

Hello,

someone knows how UE4-internal texture painting is working?
I mean the texture painting in the UE4 paint tools (or paint mode).

I have done vertex painting and understood what to to for vertex painting.
But I did not get texture painting done.

I also found documentioan only about vertext painting, but not about the texture painting option. In UE4 Release notes it is written, that there are changes on texture painting on 4.16, I gues the full Texture Painting UI is new at 4.16.

To be sure we speak about the same thing, look for attachment: Texture_painting.png
This is what I try to use.