The assessment center starts of with an induction, where everyone joins the call and get a briefing of what the day will be like. the first activity for me was the group task, you are given 50 minutes to read some content about a scenario (scenarios vary) and after you get 20 mins to discuss it with the other people in your group. my group was 4 people including me. try to stay engaged in the conversation even if you dont know whats going on. at soem point in my conversation i didnt know what they were talking about icl but i just started asking questions and thats what kept me engaged.
the second activity is similar to the group task but its a 1 to 1 with an assessor. you are given some content to read dont remember how log i got i think like 25 mins, then the assessors will begin to ask you questions about the situation. for me i was was given a manager at a cinema and the content was just a bunch of information about the cinemas performance, the assessor was mainly asking questions about how the cinema was performing and what i think could be done to improve, things like that. in this stage icl you cant waffle your way out of this one, actually read and understand the content. if you get a question which you cant answer, ask the assessor to rephrase - happened to me but after he rephrased i was able to answer the question.
the last activity is a 1to1 interview, easiest part, you have someone asking you questions similar to the video interview questions we got at the start of the application process. things like what would you do in this situation, give me an example of you showing resilience etc (make sure you use STAR to answer the questions its really helpful). Honestly, idk about anyone else but the interviewer i got was a nice guy so didnt feel like an interview more like a conversation. try to be yourself dont over do it and act like youre someone your not.
this is what my assessment center was like, i doubt it would be too different but you will definitely get a different scenario, hope it helps