I assume you're using loops and need to change their tempo, yes? Otherwise, I don't know why you need to mess with tempo. I have never used loops in Audition, but here's a quick paste for you.
Tempo
Specifies session tempo. Any loops that have a tempo specified will be time-stretched to match the session's tempo. The time-stretch method used is determined by the individual loop's settings. If you need more detailed tempo settings, right-click on the horizontal ruler in Adobe Audition's Session Display.
* Beats/Minute specifies tempo.
* Beats/Bar specifies time signature.
* Beat/Length specifies the length of each beat. (Enter 4 for a quarter
note, 8 for an eighth note, and so on.)
* Ticks/Beat specifies the number of ticks per beat.