This is the right topic, yes. But if you look at the first post you’ll see that the next two books have already been selected, so the books have been decided into mid-March. That means there will probably be another poll at the end of January or beginning of February.
This is decided per poll by simply voting for the books or manga you want to read at the time. You don’t vote for a style. You vote for a specific book/manga. The first post also includes the current list of nominations. In the Beginner Book Club (here), most of the options/winners are manga, but regular books do get picked as well. In the Intermediate Book Club, it’s mostly books.
Also, it looks like there are only six nominations right now, so feel free to nominate some more options if you have something specific in mind.