Please see the supporting documentation in the amateur-radio section of https://github.com/jwmarcus/guides/ for more information.
You will also need a copy of either the linbpq or the pilinbpq binary.
pitnc_getparams, pitnc_setparams, linbpq, and pilinbpq are Copyright of John Wiseman, G8BPQ. This repository only offers a mirror for personal project purposes. You should get the latest version and license information from the LINBPQ site.
You will also want to symlink the service file to your systemd folder with something like sudo ln -s /home/pi/src/ax25-bbs/linbpq.service /etc/systemd/system/linbpq.service. You can then enable the service at start with sudo systemctl enable linbpq.service.