You do a simulation where you basically answer fake phone calls and have to simultaneously type as fast and correct as possible. Then I believe there's a portion where you have a words per minute calculator. All of it is designed to have you feel stressed because there's a timer and nobody ever finishes. That's not that point.
Then you might get a role play where they put you in a cold room with a phone, give you a small packet with a scenario you'll basically be role playing, for example. Mine was a car wash, they tell you about the business and the different levels of car washes. Then the interviewer goes into another room, gives you about 20 or so minutes to read all the material. Then calls you, acts like a customer. They'll drop hints "I have a lot of kids and I don't have too much time ever" so you'd recommend the express wash. Basically they're looking for if you can not freak out and just generally TRY to mention one of the packages. I recommend taking charge and TELL them what wash to do. Nothing to be nervous about.
Then you take a drug and background check (VERY rigorous and btw they test your HAIR sample, and drugs stay in hair for about 6 months or so. So if that's you, do yourself a favor and don't apply)
Then final interview with the manager which is basically standard stuff. Ask why you want to sell, tell examples. Just sound genuine and interested and excited.
Honestly they hire anybody. Lately it's a lot of people who used to work at fast food places, comics shops, unemployed for years. Just have a pulse and don't be a COMPLETE screw up (which honestly is VERY hard to find apparently) and you can get the job. They're not picky.