Adding Google Analytics to Vigor child theme

Hi,

I’m a bit stumped. I need to add Google Analytics to my WP site, but I’m unsure as to how I do this, as the instructions I’ve found online don’t seem compatible with the theme I’m using. I’m not too keen to adding another plugin as I don’t want to slow my website down, so all I want to do is to add some code somewhere to activate Google Analytics.

Can anyone add any thoughts or suggestions?

Thanks.