Question: I've seen a lot of different topics and suggestions on aligning and inputting buttons/text, but the ways I've seen seem kind of risky.

What is the optimal way, for example, to add two buttons, stack them together, and have them be 10% from the bottom of the screen, and centered horizontally on all devices?

Answer: 
Learn Auto Layout if you haven't yet. Use constraints for achieving the following:

> 
> 1. For centrally Horizontal on all devices: Use Center X with SuperView.
> 2. For having them 10% from bottom, use multiplier value say **0.10** .
> 
> 
>
For iOS 9, an even simpler Auto Layout approach would be to use [UIStackView](https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIStackView_Class_Reference/).

As you can see, no constraints are needed for the buttons embedded in the stack view, as the stack view lays out the buttons for you. All you have to constrain is the location of the stack view itself.

Here's an example of two vertically stacked buttons, 10% from the bottom of the screen, and centered horizontally for all devices.

[![enter image description here](https://i.stack.imgur.com/izHwx.png)](https://i.stack.imgur.com/izHwx.png)