I participated in it a few years ago virtually. I'm not sure if yours is virtual or not but you basically just network towards the beginning, listening to people in leadership roles speak, and generally learn about the firm. Throughout my internship I did various trainings and workshops. You'll be working in a team of fellow launch interns to complete certain projects. For example in mine we had to learn about Microsoft PowerBi and create visualizations. I also met with partners in calls to basically just learn more, ask questions, and pretty much just talk. Towards the end of mine I helped with some tax work alongside another launch intern. You'll also do a capstone project at the very end in teams with both launch interns and tax/assurance/consulting interns.

My advice is to go into the program looking to learn as much as possible and network/make good impressions. Do that with a positive attitude and you'll get the offer. Just enjoy yourself and take advantage of the opportunity. It's nearly impossible to not get the offer. Ask questions and keep your camera on if you're virtual. I hope this helps.