Intern

The first step was completing the application form online and uploading a CV (no cover letter). I believe you automatically get selected to take the test as long as your undergrad GPA is above 3.2 (got an email 15 minutes after I completed the online form at 3 AM London time).
The first test has four sections: two involve numerical reasoning and math problems that you have to solve using data they provide in a few exhibits; the other two are SJT type of questions. This is not timed.
If you do well on this test, you are asked to take a second test. Here you will be asked to respond to SJT questions through video recordings. You are given a few seconds (up to two minutes) to prepare an answer and a couple of minutes to respond. The final question was a mock case where you have to advise a fictitious client on whether to acquire a certain company or not from a pool of target/potential companies.