Hello Limabean,
Well, where to begin. I think the website angelreiki.nu is a good place to check out. Vincent Amador has provided complete Reiki I-III/master and Karuna Ki manuals that you can read there. The Karuna Ki manual is the one I use when attuning others. Another site that has Reiki I-III/master manuals is at solarraven.com.
As far as I have been taught, one would progress through the Reiki I-III/master level attunements (with all the practice included), then progress to Karuna Ki (which is not necessary, but some are called to it). Also, there is no starting over. We are born with the ability to channel the Reiki energies. Once we realise this, it just grows in intensity. I feel that even if we learn everything there is, we will then use what we feel works best for us.
I am happy to be here for you. Write me back if you would like to correspond. Relax and let the Reiki come to you.
Blessings to you,
Janet