No, you will not be automatically charged. Only those who have completed the trial period, which lasts for a week, will be charged. Simply downloading the app or using it within the free limit will not incur any charges.
You can follow the instructions provided in this link: **https://support.apple.com/en-us/HT202039**.
Could you please try following those steps? Please note that deleting the app itself does not cancel your subscription.