Hi eugenia,
There are tons of examples that should be located on your computer when you install the Traditional NI-DAQ driver. However the process is not always intuitive. There are a few KBs that outline how to install these examples depending on your driver version. If you are using Traditional NI-DAQ 6.5, 6.6 or 6.7, then use this KB. If you are using Traditional NI-DAQ 6.8 or higher, then use this KB. Here is a great resource for finding help with all of the Traditional NI-DAQ functions.
The only include file that you needs to be added besides the usual libraries is nidaqex.h.