Hey!
With restructuring case studies, the emphasis usually shifts from "should this deal happen?" to "how do we deal with a company in trouble?". Therefore, you'll typically be given a scenario where a business is under financial pressure, and your job is to diagnose what is wrong and think through realistic solutions to assist the business. This could involve looking at cash flow issues, debt levels, or external pressures, and then considering options like refinancing, selling parts of the business, or some form of insolvency process. I'd say that a big part of what they are assessing is whether you can think in a balanced way and reach a solution that benefits a wide variety of stakeholders (e.g. creditors, shareholders, and management).
Capital markets case studies are also slightly different, and tend to be more about advising a company on how to raise money or access the market. Therefore, you might be weighing up options such as issuing shares versus taking on debt. The focus is less on technical knowledge (so try not to panic too much!), and more on your ability to think through timing, market conditions, and risk - essentially, you should show why one option might be more attractive than another in a given situation.
In terms of structure, I would say that they are actually quite similar to M&A case studies. You still want to clearly set out the key issues, work through the options in a logical way, and then land on well-reasoned recommendation - the main difference is just the context.
For preparation, it might be worth getting familiar with the basics of restructuring (like the different routes a distressed company can take and how creditors rank) and keep an eye on the wider economic picture in your commercial awareness preparation, particularly things such as interests rates. I always found Investopedia handy for learning new concepts, so it might be worth checking those out! Additionally, Jaysen has recently released a video that explains
Corporate Finance, which I'd definitely recommend to provide some wider context
Best of luck with the interview!!
@Abbie Whitlock
Here's to many more peaks and troughs, as well as new friendships along the way! 
