The process begins with an informal meet and greet such as at a pastry shop. You'll meet with a member of the team of your rank or level of experience and it's more of an open discussion. This seems to be more to tell if you're a fit for the "culture" though I would imagine that if you do a poor job talking to your experience (i.e. elevator speech) that too could disqualify.
Should mutual interest be established at this session, you'll then be brought in for in person interviews with a handful of Senior Managers and eventually a member of the executive team. This can happen over the course of 1 interview (multiple hours) or be broken into 2 2 hour interviews often with a dinner / lunch on the end of the last interview.
If you're telling the truth and have the experience you claim you do on your resume or have talked about previously with Sendero, you will find the in office interview(s) manageable. I'm not going to call this easy though, I was quite well prepared and still found myself having to take a pause on a couple of occasions before responding to questions asked by a couple of interviewers in particular.
That said, even as you're grilled (yes, there is one interviewer who pushes to the point he has a reputation for it) you can tell the interviewer wants you to succeed. Don't let the pressure applied throw you off track in your responses and you'll see
Lastly, I can't stress enough how important each and every interaction is. Do not take your initial informal interview lightly and do not take the dinner / lunch lightly should you be fortunate enough to make it that far. On the surface these seem like nice to haves but, they too matter.