A list of pre-built variables appears. You can select from different categories (in this case, All, Top, Bottom, Contributions) ) or search for your own custom variable
Search required variables on the given Search Built-in Variable bar and select a suitable option from the suggested list
An additional box opens up, where you can see the value/s contained within the variable
Provide a Variable Name and save. A notification of successful variable creation will appear at the top right (Note that you cannot give spaces when providing a Variable Name)
You can also reconfigure your variables by hovering over a variable name and edit/change the inputs