Help! Auto-renewal for app subscription

I just downloaded an app on my iPhone (the 4S if it makes a difference). I’ve decided I hate it, and want to cancel the monthly subscription that automatically will get charged to my iTunes account each month if I don’t. The “Help” portion of the app, which wasn’t that helpful in actuality, eventually explained I could cancel the monthly subscription if I turned off the automatic renewal feature in my ITunes Account Settings.

I have no clue how to do this. Can it be done from my iPhone, or do I have to use my PC? Either way, can someone walk me through this? I’m not exactly iTunes or tech savvy, and this was my first subscription purchase ever. Thanks!!!

Does this help?

You rock. It got me to where I needed to go. Thank you!