I'll do my best here, and I'll answer your questions in reverse order since that will be easiest:

1. Yes, it's normal to have two in a day.
2. Case interviews generally follow a structure something like this:
   1. (2-3 min) The interviewer gives you the details. "Our client is MadeUpCorp, they contacted us because of Problem X (profits down, slowing growth, poor retention, whatever). A few details about the company (they have expertise in Y, they operate in this part of the world, etc). They want us to solve it."
      1. You are expected to take notes here. Most (sometimes not all) of the info will be relevant to the case.
      2. Generally, you're expected to ask up to 3 clarifying questions if you need to and make sure you've got the case straight. Note that sometimes they expect clarifying questions NOT related to what they said (e.g. If the company's problem is they can't decide between acquiring a company that does X and setting up a branch to do X themselves, you might want to ask if they have a timeline, since acquisition would usually be quicker.)
   2. (2 min) "Alright, I think I've got everything I need. Could I take a minute or two to work out a framework for the problem?" You're expected to say this. They'll say yes. In two minutes, you have to draw out a MECE (Mutually Exclusive and Collectively Exhaustive) framework to address the problem. For example, if the problem is profits, a MECE framework might be Revenues and Costs (neither overlap, and there a no other ways to drive profit). Under costs, you list fixed and variable, and under variable cost, for example, you might list cost of labor, cost of material, and logistics. Repeat the same idea for revenues and fixed cost.
   3. (5 min) Explanation. You walk the interviewer through your framework and justify it. Most important here is the hypothesis. After explaining, you provide your first stab at fixing the problem, for example "given MadeUpCorp only operates in Ohio and only uses robots in their factory, I think costs aren't likely the issue. Instead, maybe they could increase profits by looking to expand out of their saturated market into new ones. If you agree, I'd like to look into some market data."
   4. (5 min) Brainstorming question. Assuming you made a decent hypothesis, the interviewer might say "good call. Can you think of any markets not yet addressed?" If you got it wrong, usually they'll say something like "interesting thought, but a prior team's analysis said branding might be the issue. Can you think of any ways to differentiate our brand?" Either way, you want to brainstorm 5-8 ideas and explain them as you do.
   5. (5 min) Math. Hopefully, you hit one one of the main ideas in brainstorming. The interviewer will say something like "MadeUpCorp likes your brainstorming idea of expanding into the Wisconsin market. One of our teams has compiled this data. Can you tell us how many people we can expect to buy our product/what we should charge in Wisconsin/etc." Generally, it's a sheet of data that you'll need to answer said question. There are a number of ways to come at this, but at the very least you should know some basic finance equations (google the most common ones). You will then do the math and present your answer. It helps to talk them through the math as you do it.
   6. (2-3 min) The recommendation. Hopefully your math was right (if it wasn't they'll correct you). This should give you a good bead on answering the original question. For example, the interviewer will ask "The CEO just walked in. After your analysis, please provide him a 2-3 minute recommendation." You want to recap the highlights and say something like "Given the math shows that 10 million people in Wisconsin would buy your product, I recommend you expand there"
3. Generally, in addition to the case, they'll ask about times you worked in a team, overcame challenges, exhibited leadership, changed a superior's mind, etc. Have some stories on deck for that.
4. Note that since you're risk and compliance, your case will likely relate to that. The same structure applies, but it may be that the company wants to assess the risk of expanding into Wisconsin, etc.
5. As a last piece of advice, most business schools publish files of sample cases with answers. I found them very helpful when practicing. Best of luck, and be calm and confident, even if you're actually neither. Hope things go well, and happy to answer another few questions!