All right, so I just got a different phone and I never really used any data or wifi on my old one so don't judge me if I don't know what I'm talking about, lol. But this one is a Samsung Galaxy s4 mini and I don't know if I'm using data or not. I'm not supposed to use data and frankly, I don't want to. But at the top of my screen, I see it says 4G and stuff. The arrows are blinking as well. My sister went on my phone and had signed in on the Google play store app thing. And I think that's what's using the data. How to I stop using the data and how to I disable or take out the email? I really need help and I don't know what the hell to do. Please help! Please also tell me step by step so I know I didn't do anything I'm not supposed to again! Thank you!

Turn OFF Mobile Data.
Downward swipe from the top and there's an icon on the list that appears.

Lol, thank you so much. I'm terrible with technology and I know it. >.<