MS paint like 2D drawing interface


I am absolutely new to Unreal but confident that I can pickup things quite fast as I have solid programming skills.

I am trying to develop a FloorPlanner application with Unreal.
I need to develop an user Interface with below features. (The interface looks similar to the images attached)

  1. There will be menus left side and a canvas at right side. (I don,t think we can achieve this with Unreal. The UI will always be overlay on top of the game. Please confirm)
  2. The app should be able to render both 2d and 3d views. (User can switch between 2D and 3D modes).

In 2D mode:

User draws lines with mouse/touch. Each line is a wall. (Assume that the 2D mode will be similar to MS Paint in terms of look and features).
User marks positions of windows.

When switches to 3D mode,

Walls and windows are created dynamically with Runtime Mesh Component and rendered. (I know the logic for projecting 2D to 3D).

I am not getting any idea on how to start.

I request you to help me in my baby steps. Thanks in advance.