I actually felt that the instructions weren't that clear if you were joining via the app. I incidentally did join some of the rooms after the actual conference,

I actually felt that the instructions weren't that clear if you were joining via the app. I incidentally did join some of the rooms after the actual conference, but FOSDEM could have provided more instructions beyond "sign up on our server and use the web client" - the main Android App client, and most popular server are hardly niche. And many people already have that setup. I did eventually work out how to find the chats - but it took me a while too