There are many standard examples in LabVIEW that will help you do this. Simply go to Help -> Find Examples -> etc...
I'm assuming of course that you are using LabVIEW. If you are not there are many examples in other languages if you are using LabWindowsCVI or Measurement Studio.
If your not getting the DAQ Assistant you should make sure you've installed the latest version of DAQMx. ni.com/support.
Regards,
Superfly