My wild guess is it will be on their YouTube channel:
www.youtube.com/@world_wave_tour/WWT communication strategy is a bit lacking. Sometimes events have their own web site, sometimes they seem to have an event page on the PWA website and sometimes they are buried deep in the WWT web site. There is some random stuff on Instagram but you need to either go specifically to their Instagram page or hope the Instagram algorithm serves up the right content. And then there is a Facebook page which has the event times but no links.
If you are subscribed to the WWT YouTube channel you should get a notification of the live stream in your subscription page.
Would be helpful if they had a consistent way of communicating these events. But I guess in the age Instagram, TikTok and AI web pages have become an afterthought so you are left with either hoping the algorithm serves up the content or you have to chase the content in 5 different spots.