This is not a kata issue, and we don't know with what you wrote what you don't understand. You can go to Codewars Discord channel for help.

Seeing your current code, you've copied and pasted in the Solution tab, the content of Sample tests tab. Click Reset button and start over, you only need to write your code inside the function in this kata:

def sum_array(a):
    pass

Replace pass there with your code. Please read the docs if you're confused on how every tab works: https://docs.codewars.com/getting-started/solving-kata