I'm relatively new to coding and am having trouble.

I have this code to send data to firebase

app.userid = app.user.uid

var userRef = app.dataInfo.child(app.users);

var useridRef = userRef.child(app.userid);

useridRef.set({
  locations: "",
  theme: "",
  colorScheme: "",
  food: ""
});

However, I keep getting the error:

  
FIREBASE WARNING: set at /users/(GoogleID) failed: permission_denied 
      2016-05-23 22:52:42.707 firebase.js:227 Uncaught (in promise) Error: PERMISSION_DENIED: Permission denied(…)

When I try to look this up it talks about rules for Firebase, which seems to be in a language that I haven't learned yet (or it is just going over my head). Can someone explain what is causing the issue? I thought it was that I was asking for it to store email and user display name and you just weren't allowed to do this, but when I took those out I still had the same problem. Is there a way to avoid this error without setting the rules, or are rules something I can teach myself how to write in a day, or am I just way out of my league?

Thanks for any help!