I recently went in for their assessment day in NYC. I will be starting training in a week.
The assessment day consisted of an hour long written test and two one-on-one interviews. The test is composed of some technical questions, some project management questions, coding examples and questions on them. You don't need more than a first semester programming course to answer the questions about the example code. If you're a project management applicant, I believe they mark you more leniently because they don't expect you to have a background in programming.
My first interview was a technical one where I was asked about the skills I wrote on my resume (if you wrote something there, you better know it - at least somewhat) and I was asked to show some code I had written.
My second interview was more to see how interested I was in FDM in general, what fields I'd be more interested in, how my previous experiences (work + college) affect my ideas about how my career should look in the future, etc.