I applied online. The process took 1+ week. I interviewed at Save the Children UK (London, England) in Dec 2020
Interview
Shortlisting followed by a 1st stage interview and finally a 2nd/final stage one.
I wasn't given much time to prepare for the interview. Literally got a call at 4pm inviting me to the interview the following morning. Wasn't given much time for asking questions (note: that one of the interviewers were late to join the interview, meaning less time).