Im having problems with loop. Just for test, I created a real basic flow that generate a random number, and a google sheets action do add data inside a cell, as #index and #item.
You can refer this guide for loop piece in details.
For your use case, if you want the loop to run 7 times, you need an array of 7 items from the previous step. If you are receiving an array from the ChatGPT step, you can directly pass it to the loop step.
Can you provide additional details regarding the specific objectives you aim to accomplish with the loop, I would be more than happy to offer further assistance and guidance.