Adding an element to an array: Push and Append replacing the array, rather than adding on to it

Hi! I've created a Function with a For Loop, where at the end of the loop, a new variable is created, and I want to add this variable to an array. I've tried both Push and Append. However, with each one, the entire array is replaced with the new variable as an element, rather than the new variable added on to the end of the array. Here's a video showing my set up and the results: https://www.loom.com/share/7dbd4aa6f2864916a809b30eee48946c

I didn't show it in the video, but I also tried Merge, which ended up with the same result as Push and Append shown above. Thanks for your help!