Unfortunately you don't get to be a SSA (Supervisory Special Agent) When you first get into the Bureau. You need a lot of experience before being a SSA. You need to be a Special Agent first. It may take some time before you can be a SSA but when and if you become one you'll understand why.
It takes a lot of knowledge of what you know in your unit, responsibility, and you must have a sense of authority. Actually you apply for a job in the FBI whether it be Anti-terrorism or the BAU. If they have a spot open you can apply for it but you need to pad your resume pretty impressively. Tons of people will want to get the spot. Knowing More then one language will help along with an impressive college and degree.
