You should add a screenshot of your code and the settings of your array.
If you need help to learn arrays, I have done some tutorial during my course for the creation of a card game with battle grid. I am using Construct 2 in the videos, but it works with Construct 3 too.
You can check some of this video that might help you:
Array Introduction (Theory)
Shuffle a Deck of Cards in an Array + How FIFO and LIFO works
Place elements in a bidimensional array
The Array is used in other videos of the course, but these should help you to understand even without following the course since the beginning.
I hope it helps :-)