GA code to themes functions .php

In regard to my post previously, my hosting company has resolved the problem and I can again access the admin area of my wp Twenty ten website. However, I have yet to load GA tracking code. Is there a specific place to enter it when you do it manually?

I don’t think I’ll bother with the instructions from: http://www.wpbeginner.com/beginners-guide/how-to-install-google-analytics-in-wordpress/

again, incase same issue.

With regard to a GA plugin, what do others think of the security and access from a third party to the data?
A plugin would be easier but I dont’ want to jeopardize the security of my GA account and data.