Can someone do a write up on how to properly use a VPN

Just so that you know, HN is the worst possible place to ask general questions.

But I'm more curious to know why you think a VPN will keep you "secure" on social media? All a VPN does is change your ip address; what threat do you think that protects you from? Social networking is for learning about people based on their behavior, and then showing ads to them. That primarily means the content, frequency, and nature of people's interactions with other people and with content such as videos and articles. Your ip address is irrelevant to all of that.

Try /r/VPN, /r/privacy, and search into HN posts over the past year related to endpoint security (start with anything that has 'security' in the title and filter from there.)

Securing your devices is one thing, security your connectivity and communication channels is another, and opsec as it relates to social media is another. There are better forums for this and most of the data is already out there if you look for it.

The most blatant thing is to never install their applications, extensions, or any native code.

It immediately blows through your VPN.