english is not my native language but in your IVR, if you want to wait for the user to press a key, in your configuration file, you have to use the "WaitExten" function that will wait for a new extension. Such extension will then replace the extension that originated the call.
exten => s,1,PlayBack(...)
exten => s,2,WaitExten
exten => 1,1,one action...
exten => 2,1,another action
After the WaitExten function call, if the user has pressed the "2" key, then "another action" will be started. If the user has pressed the "1" key, then "one action" will be started, and so on.