The whole process took a month - from the first interview to the last round and receiving the 'no go' email. In general, I can's say that the interview process is any different from those in bigger companies, pretty generic emails, getting a how to guide for the process etc. I did kind of know at one point that there is this corporate black hole that sucks you in, and during the last round I definetly knew I don't want to work here.
The first interview was the generic HR screening, asking about you, your background, experience, salary range (be ready for it even though they ask it when applying), how you cope with pressure, how do you thrive in a team etc.
The second round was with the manager, and they asked me specific business case questions, and asked to explain my rationale. I found this to be quite vague, as if I was being led to a correct answer. What I thought was strange is that I knew these questions regarding variables will all be known once in the company, and you'll just learn all there is about the system, operations, and variables.
The third part was the business case - an excel sheet with data, and a list of questions. The deliverable was a presentation to the stakeholders. You are encouraged to think outside the box, which I think does not really reflect the reality of the position.
The fourth part is a panel where you present your findings, it's an hour long presentation including their questions. It was very disheartening to me personally as I've spent time preparing, and I felt as if the questions were a bit over the entry level position, maybe even a bit on the product manager side. There are a lot of why's (the thing about these questions is that they tell you: it's not that - so you need to know the right answer without knowing the system = think outside the box).
If you are preparing for a similar role, make sure you learn all their 6 core values, this is really important, and chose top two and a very concise explanation why. My second advice would be to reach out to someone working in a delivery company and just ask domain related questions - for the purposes of your business case. A Product (operations) manager could also help, for sure.
I am sure anyone with experience working in delivery companies would have a really good shot.