You find there three different elements:
It is the menu where you can create and edit the Global Variable List that you can use in your application. In computer programming, a global variable is a variable with global scope, meaning that it is visible (hence accessible) throughout the program, unless shadowed. https://en.wikipedia.org/wiki/Global_variable
Here you will have two different elements listed. The ladder diagram and the Arduino code. By clicking on each one of the elements listed you will switch between them.
By clicking the element on this section you will move to the area to create and edit the IO Mapping of your project.
Central Working Area
Here you will be able to work on your ladder diagram, Arduino code, or creating or editing Global Variable List or IO Mapping.
This area is only functional while programming with ladder diagram.
Here you will be allowed to edit some properties of the selected ladder blocks.