Applied at John Lewis for Customer Assistant

I applied for a Christmas temp position as a Customer Assistant at John Lewis and have both a group interview and a one-on-one interview scheduled. Since I've never experienced a group interview before, I'm feeling a bit anxious and would appreciate any tips or insights on what to expect. A friend of mine interviewed for the same role last year and only had the group interview, so I'm curious if this is a common practice. Looking forward to any advice!