Just a very short message to direct you to my article on statistical significance over on the Kissmetrics blog. The emphasis is on intuitive means to understanding the key ideas.
Check Out My Guide to Statistical Significance on Kissmetrics
Fun, example-filled guide, aimed at building intuition
Rationed views, gas pedals, per person frequencies, when to trust platform reps
The general principles of targeting followed by a tour of the available options on the major platforms
Separate language from territory; clarify your international site structure to Google