EXP Realty Stock - how does it work?

We see a lot of people talk about EXP Realty Stock (The stock, the stock, the stock!)

But what I don’t see often is an explanation on how it works.

Like you get EXP stocks when you hit icon?
You can buy extra, but get a discount?
EXP Realty gives you stock, but they have to vest for a period?

Can someone please explain how all this Exp stock stuff works?