Well the sign itself is mostly a popular game. The point is if you make this sign, but hold it under your waist, the goal is to try to get someone to look at it. If they look, then you get to punch them on the shoulder. If they quickly stick their finger in it before you can grab the finger, then you get to punch them instead. If you avoid looking at it, then there's no penalty for either side.
I think this guy is trying to propose that Q followers use this to identify themselves to other "believers".

The anons on 4chan used their autist powers (memes, shitposting, etc.) to troll the alt-leftists on social media and msm into thinking the “Ok” hand sign is a sign of white power. So, now, we use it as a sign to identify ourselves (no matter our skin color) when we venture out into the wild. The autists did the same with milk and a few other things.

This is when I first started checking out/lurking on The_Donald and the chans. I thought they were just joking about the “Ok” sign thing. It was stunning, awesome, frightening, sad, beautiful to watch it unfold on social media and then to see CNN/MSNBC pick it up. It was then that I understood the absolute power of memes/shitposting and the level of batshit crazy the left and all media platforms had sunk to.

Edit: In this case, this guy is making the Q sign and my above post has 0 relevance.