When a new OFW update comes out, just check the boards to make sure it's safe to update. 9 out 10 times nothing major was changed and it's safe to update via the system settings. If something does break in the OFW update (it's rare, but has it has happened,) just wait until it's been fixed (typically takes a few hours to maybe 2 days at max,) then update your CFW, finally updating your OFW through System Settings. Always check the boards before updatings, chances are high that several members (me most of the time) will have tested the update first and reported back the results of the tests.
You do need your SD card in the system the whole time,
The Guide does include sets to moving the CFW to the CTRNAND.
