Three stages: 2 x 30 mins teams (one focusing on technical experience, then one with HR on more general/cultural-fit aspects like why have you applied, what is your ideal role, how the location works for you etc), then 90 min in person including giving a presentation. Very nice friendly people.
My advice: use the opportunities to ask lots of questions to find out what the role entails so that you don't waste everone's valuable time applying for something which is not for you! For example, this was a Director role and I didn't find out that there might be a need to be quite hands-on (e.g. writing tech specs etc), and therefore not what I was looking for in a senior leadership role, until the final interview and post-interview feedback when I'd already spent many hours preparing. This is a young organisation and very different to larger established companies where Director roles are generally rather different.