How to link NED Files to simulation in opp_test omnet

I am new to OMNeT++. I am trying to use the opp_test tool for testing, however I got problems for linking and loading some NED files that I implemented and use them in a simulation test.

Now, my project is organized like this:

root
  simulations
  src
    Lib
    Modules 
      Node1
      ...
      NodeN 
  tests
  work

So, basically in the test I want to create a network using some nodes I defined in src/Modules, run it and check the output. According to the simulation manual, there are basically 3 steps for the control script. 1) opp_test gen in order to generate the files and here I should not have any doubts; 2) compile: here I have a doubt. Should I compile the code in src and the file generated together? 3) opp_test run: here I should export before the NEDPATH. But it is the path of the ned files that I want to use in src/Modules or also the NED of the network I generate?

I have also seen some problems related to the package in the files that are generated. If you could give me an explanation what I should care in this process, I would appreciate.

Thanks!