Tips on forming a tenant's union?

I've been considering building a tenant's union but I've never heard of anything like that over here before. A lot of the advice I see on the internet is about laws, which doesn't transfer seamlessly to here.

Since rent prices have gone up a stupid amount since the pandemic, with no sign of going down despite our economy looking much better, it seems like a good avenue for some practice.

Anybody have any experience with starting one from nothing like that?