We are having trouble adding constraints to our app, can anyone help us?

Do you mean that you can't get any contraints added to your UI?

OK, so understanding how AutoLayout works can be a long and daunting road... but iOS9 made things a whole lot easier to get going with the introduction of Stacks.

To get something up and running, you could:

1) Put your buttons and text fields in a Stack

2) Center the stack horizontally and vertically on the screen

Then, you should find something shows up on the screen when you run the app.

Honestly, though, undertanding how to build UIs in Xcode takes a bit of practice. No subsitute for putting the hours in to lean it.