Understanding Connection To Proxy Ratio

I am watching looplines video on safely scraping google in 2020 and am having a fundamental misunderstanding on the terminology.

It says that there should be one connection for every 5 proxies, or that the connection ratio can vary.

How can more than 1 IP address make a single connection? When a page loads does it not load from a single IP?

How would it be possible for 50 IP addresses to load one connection?

What does “connection” mean in this case?