Hi punsith,
You can find the pin out diagram on the 6023E on Pg. 12 of its user manual:
http://www.ni.com/pdf/manuals/370719c.pdf
You can also open up Measurement and Automation Explorer (NI MAX), expand out Devices and Interfaces, right click your device, and view the Device Pinouts.
If you go to our example finder (Help > Find Examples), you can find examples of basic data acquisition tasks under Hardware Input and Output > DAQmx. We also have this getting started guide for programming using our DAQmx API. I hope this helps!
http://www.ni.com/product-documentation/5438/en/