If you download the "Google Analytics for Wordpress" plugin you just need to go to settings and insert your Analytics Account ID.... that's assuming you already created an Analytics account through Google.
Same thing applies. Script is Script. You can add the script directly into your theme files where you want them to appear. Some themes have "hooks" where you can inject them into the theme at specific points (check your theme docs for that info). You do not need a plugin to do this for you. Although, it is good to know your Html and a little bit of Php to stop yourself from mucking up the works. Once learned, you will not have a need for 95% of the plugins out there.