Well, that's the difference between a manual, and a tutorial. Many confuse the role of the two....

But you often get a Quick Start guide (I know Roland do) and often this is quite informative, and more tutorial in nature.

To be honest, if most people would approach learning a new OS methodically, rather than shot-gunning themselves with everything immediately, to try and regain their familiarity with their old arranger as fast (or faster!) than possible, things would be a little easier.

Rather than go 'Today I want to play an entire tune', you go 'Today, I'll just learn how to call up styles', and learn all the different ways to do just that one thing, with all the differences memorized for each method (registration, free panel, tempo hold, etc.). Then the next day it's 'Today I'll learn how to call up the Voices'. Rinse and repeat...

Taken this way, a completely new OS is FAR easier to learn. But confusing yourself with too much information for the sake of instant gratification is a sure way to frustrate yourself.

And never forget just how long it took you to get truly familiar with your old OS. You REALLY ought to expect any new OS (unless related by manufacturer) to take at least as long, and probably longer. You've got to forget your old way AND learn totally new capabilities your old arranger never had. I think many people forget the months they spent mastering their old arranger, and expect to master a new one in weeks (or even days!) and end up going 'This new arranger sucks!', when in fact it is their patience that sucks!

Just be patient and methodical, and realistic about your learning abilities, and it will come together. Just not as fast or as easy as you would like!