Upgrading Domino 6.2.1 to 7

Why? Well because we pay for the software maintenance and apparently release 7 is hotter.
What do I need to do.
I've been trawling through the upgrade notes.
First off, I need to convert our flat name scheme to hierachical: that needs user input. Not always a good thing.

I guess we would have to kick it off by adding an org unit to the domain?
( well I've done that now) and yes, I've RTFM'd already.

addenDUMB --> doh! erm yeah we already are hierarchical, you don't need an additional org unit. Pffft. Obv. RTFM, just didn't take it in.