First you submit you application and take a personality test. If you know someone in the company, this first portion of the application process is essential skipped through their recommendation. You will then submit a writing sample, if you are applying for a quant position this should be a quant paper. Then you take a quick phone interview. Then you get a homework assignment to complete. Successful candidate will then get an interview with the quant Manger, an assistant quant manager, and the head of either the higher ed, k-12, or enterprise department, depending on the team you are being considered for (I do not remember much say in this).