The Advanced variable macros allow you to access enumerable variables values (lists,tables, dictionaries, datasets) easily without having to use macros functions. It's a macros code that you write in the properties of the command text fields that will allow you to access data in your project fast.
Also instead of the index number, you can also use a function like:
rand: to get a random index within the limit of the list
first: to get the first index of the list
last: to get the last index of the list
count: get total items count of the list