 
            If you are not familiar with Linux, I'd suggest the LTS (Long Term Support) release. Once you've got Ubuntu installed, you can use
git clone https://github.com/boatbod/op25.git
to get a copy of boatbod's version of op25. Once that finishes downloading,
cd op25 ./install.sh
should get you a working install of the software. Beyond that, there are a lot more people that can help in the RadioReference forums than there are here so I'd suggest visiting
https://forums.radioreference.com/software-defined-radio/