The first starting step for this would be to apply Patch 17204589 (17204589:12.2.0) on the Run File System before proceeding to the next steps if you haven't already applied Consolidated Seed Table Upgrade Patch 17204589 (17204589:12.2.0).
Blog | Feb 3, 2014
Blog | Jan 31, 2014
During the upgrade you will notice the use of backslash at the end of each line. This has a significance and is used to divide each command across several screen lines for readability.
Blog | Jan 30, 2014
One of the important things to keep in mind during the installation is after laying down the File System using the Rapid Install, do not change the password for any products.