The entire process, from application to in-person interview, was around a month. There was first a short phone interview with HR, followed by a phone interview with two people leading the editorial team a week later -- both calls involved questions about what you know about BMC/Springer Nature, your work background, and why you're interested in the position. Both calls were about 15 minutes.
The in-person interview was scheduled for the week after, and lasted around two hours. The first hour was essentially an administrative test in three parts: selecting which journals are the best fit for a selection of articles, task prioritization, and creating a mock email to respond to a client. The second hour was a discussion with the editorial team heads about previous job experience, and involved fairly standard interview questions.