Open the header.php file from your WordPress theme that you are currently using and add the Google Analytics embed code from the Google Analytics page.
Admin -> ACCOUNT -> PROPERTY -> Js Tracking Info -> Tracking Code.
Copy that Tracking Code and add it right after the <head> in the following way.
Now save the file and clear your cache if you are using a caching plugin.
You should be able to test REAL-TIME -> Overview from your Google Analytics Account now.