You will need to have a Google Analytics account and have the code that Google has supplied you to add this to your LMS.
Step 1. Select Site Administration
Step 2. Select Appearance Tab
Step 3. Find the Appearance section.
Step 4. Select Additional HTML
Step 5. Paste the Google Analytics HTML code into the Within Head text box
Step 6. Scroll to the bottom of the page and select Save Changes
The code has now been added to you site.