[Ainhoa]

Hello everybody,
I am a new user of OpenFoam. I was looking the tutorials and more or less I would say I understand the examples. But my Problem is that when I have to start with a new Simulation or case, I have no idea how to start. I was reading in different Forums and I find them very useful but I can find only answers for more advanced questions.
Until now what I did is the next:
I had the geometry in Autodesk Inventor, I exported it as STEP to Salome and I did the meshing there. I exported that mesh to OpenFoam as unv file and I used ideasUnvToFoam to convert it to OpenFoam Format. Until here I think I did it well. But I have no idea how to continue...
I supose I have to choose the most similar case in the tutorials and modify it right? But do I Need to modify all the files? And for example, how can I introduce the new geometry I want to simulate to the case I am basing on?
Apart of the Problem of OpenFoam I am not a user of Linux so I don't know it very well...
I am really lost as you can see Could somebody help me? I just Need the very first and Basic steps, or if you know some tutorial, web page, example... to build new simulations... I would be really happy
Thank you in advance,

Ainhoa