Including data in packets-Omnet++ and MiXim

[new_to_omnet]

Hi all,

Am very new to omnet..I want to simulate a WSN using Omnet++ 4.0 and
MiXim. The simulation requires some processing based on the data in
the packets. How can I include data in the packets?

Also how do I use the wireless classes and methods in Omnet++ IDE? I
have searched but didnt find any comprehensive tutorial..
Please help!!