Help using the subway?

I'm American, I'm here for about 7 days and I can't really read japanese lol. I've tried a couple times now to use the subway and I've done it wrong both times, the first I picked the wrong nakano station at first so I just got 2 tickets and then I couldn't figure out how to get out at the arrival station so I just went through the open gate and figured I'd just play stupid foreigner if questioned. The 2nd I was sure I did right, but when I got to akihabara it still wouldn't let me out of the exit gate and I had to talk to a station attendant and essentially ended up paying for the ticket a 2nd time again.

What did I do wrong? How is this supposed to work? Is there a better way to do it? I can't get suica or pasmo on my phone because it's an android, I've already checked. And I don't really want to have to buy the full month rail pass, since I'm not going to be here that long.