Warning! The preferred approach is to use Google Tag Manager because of cross domain tracking issues with direct Google Analytics integration.
Please watch this video to learn why you should be using Google Tag Manager to fire Google Analytics instead of Google Analytics directly.
If you still want to go ahead and install Google Analytics directly then please follow the following steps.
You will miss the benefits of cross domain tracking.
You have 2 options to install Google Analytics (or any other script).
Option 1: Install Google Analytics Under Global Scripts
Option 2: Install Google Analytics at the Decision Tree Level
Se video below for instructions for both options.