PiFace Real Time Clock Software Change

[fc-gituser]

Dear GitHub Community
All my Raspberry Pi devices (RPi 2, RPi Zero, and RPi 3 (planned) are running with the current Raspbian Jessie version. I have successfully installed PiFace Real Time Clock using the PiFace website instructions and GitHub.com software download on a number of RPi 2's and one of my three RPi Zero's. I have recently continued the installations on another two RPi's and cannot continue because after these two lines:
chmod +x install-piface-real-time-clock.sh
sudo ./install-piface-real-time-clock.sh
the following message returns:
create new pifacertc init script to load time from PiFace RTC
Adding /etc/init.d/pifacertc .
install the pifacertc init script
enable I2c by using : raspi-config

As I am a Linux beginner, can someone lead me through (expand) the coding of these lines so I may install PiFace RTC in the future. The changelog on GitHub refers to a revision change but I am not knowledgable enough to discuss it further. Also is PiFace RTC installation (when resolved) compatible with RPi 3.
Thank you very much. Frank.