PercentageAutoLayout
Just a quick unedited video on how to make a UIButton be 10% from the bottom of the view for any orientation using auto layout.
To get your button to be exactly 10% above the bottom of the screen:
1. Create a Bottom Space to Container (Or Bottom Layout Guide) constraint.
2. Select the constraint you just created.
3. In the First Item field, select the drop down and click "Reverse First And Second Item"
4. Set it's constant to 0.
5. Set the Multiplier to 90% (this will be 10% from the bottom).
6. Done