You will need:
Surname, Initials. (Year of publication) Title of conference paper, in: Title of conference, Location, date of conference, page range of paper. Available from: www.webaddress.com [Accessed day month year].
Walker, G., Salmon, P. and Stanton, N. A. (2015) What the Death Star can tell us about system safety, in: International Conference on Engineering Psychology and Cognitive Ergonomics, Los Angeles, August, pp. 297-306. Available from: https://link.springer.com/chapter/10.1007/978-3-319-20373-7_28#citeas [Accessed 17 February 2021].
In-text citation: (Walker et al., 2015)