About 2 weeks after submitting the resume, I was invited to complete an online test, which must be done on a BCG computer. (Other candidates with more experience were waived this test and instead only needed to do a phone interview with a recruiter.) Since there is not much prepping material for BCG Potential Test online (as compared to McKinsey PST's), I find it extremely helpful to use consulting prep websites. Just Google and many of those will pop up on top. Fortunately calculator is allowed but I'd recommend practice without a calculator. Do remember to brush up your mental math since it will definitely help you save a lot of time on easy questions. 3 days later I received an invitation to the first round which consisted of 2 back-to-back case interviews with project leaders, and was allowed about 1 month to prepare. During this time I was connected with a BCG buddy who was really nice and helped me prepped properly. It's important to have somebody to practice case interviews with, and you can find many of them online. This prepping time is really one of the most enjoying parts of the whole process since I got to know many people from all over the world who were also interviewing with MBB or top consulting firms. Closer to the interview date, they sent me the interviewers’ profile so I had sometimes to find their LinkedIn pages and got to know them more. The interviews were really case-heavy, so we spent around 5-10 minutes talking about my background before moving to the actual cases. Each interview lasted for around 50-60 minutes. Despite prepping around 20 live cases and read a lot more offline cases, I still found their cases to be more difficult than I’d expected (or I was too nervous and thus didn’t manage myself really well). 

Got a phone call from one of the interviewers, saying they would not invite me to the next round and also gave me some feedbacks, which I totally understand given my performance during the interview. Overall the process was great and I did learn a lot as well as made more friends. 

My advice here would be to prep as much as you could, remember to stay calm, confirm the case objectives, and manage your time during the interview so that you can finish the case in around 30-35mins.