Adrian,
your scattered questions indicate you have a long way to go before you can do anything useful with gnuradio on your own.
I suggest you "study" these examples carefully: you'll discover that many people have put a lot of time and love into this and have provided documentation to answer most if not all your questions.
Try to read the documentation of gr-trellis explaining how you can build any arbitrary fsm.
Then read the documentation and code for the siso modules.
Then read the documentation and code for sccc/pccc etc.
As the folder name suggests these are only EXAMPLES but this is also open source so all the code is there for you to read/change.
If the documentation does not answer your questions then please post a specific question on the list. Even better, provide your own grc draft design so people can comment on something concrete.
I am willing to help you with gr-trellis if you decide to take it seriously.
best
Achilleas