You can follow the Quick Start guide on the official site.
If you already have an SD card with a working Raspbian OS skip this entirely and start from Install Freedomotic automatically
After you have a working Raspian OS you can install Freedomotic on it.
Insert your SD card on Raspberry, boot your system and connect using SSH. On Linux write this on command line
Default password is raspberry.
Open Terminal and copy/paste this command to install and start Freedomotic automatically
sudo curl -s http://freedomotic-user-manual.readthedocs.io/scripts/freedomotic-raspberry-install | sh
Some things you would like to know: