Hi @Leandro S5,
There are a few resources available about using PLCs and FlexSim. I recommend starting at the User Manual as it will help answer most general questions. That's what I used to set up the PLC I have at my desk, which is a simple Allen-Bradley Micro820.
Unfortunately, the use of PLCs with FlexSim is not very widely used, so there aren't lots of resources available, but I'm sure it will be further developed in the future and there will be more resources available. If you run into any specific problems getting things set up, feel free to ask specific questions and we'll do our best to help.