Hi, in my opinion the best thing to do is to start with he Tic-Toc tutorial, which gives an overview of the platform. Just search for it on google and complete the different steps.

Hi Laiitha, I used Omnet++ several years ago. If I remember correctly, there is an official manual for beginner. If you have some knowledge of C++, it is not difficult to use omnet++. You can run some example codes to see how it works.  As omnet++ is a powerful tool, you can write codes for your requirement. 

It is possible  Extended  topology generation, including setting of spatially correlated initial conditions and batch script generation for simplifying modeling and scenarios generation, Trace data visualization support that identies spatialdependencies for design and debugging,  Processing and analysis of trace data with support of

relational databases for performance evaluation

how to install omnett++ ?

This tool needs some programming skill in C++

Yes, Omnet++ supports very well.

Lalitha Ananth

Please follow the OMNeT++ manual thoroughly, you will understand how to do customization in OMNeT++

https://doc.omnetpp.org/omnetpp/manual/