Complex process with multiple steps, much easier if you anticipate what you need to prepare for. Very demanding type of interview for entry level, with detailed assessment that matches what an actual editor does - so be prepared.
1.- Send materials (Cover letter, CV, assignments as appropriate: select a few relevant papers, think of a collection/series of Reviews, News and Views type of write up)
2.- Phone interview with manager/chief editor: discuss career, goals, interests, etc.
3.- Phone interview with HR: visa/work permit, salary expectations, availability, compliance, etc.
4.- Written test (online): 2-3 papers to read and discuss within 1h turnaround, make editorial decisions and justify.
5.- In person written test: 3 papers in 1h, then discuss with team, tons of questions with varying levels of precision, make an editorial decision and justify it. General view of specific field of expertise for the journal I was interviewing for. Key opinion leaders, proposed conferences, authors to look, problematic areas/sensitive topics and how to handle them. General discussion with team members.