Create a good beginner user tutorial

Just having a look at CCK, as from what I can glean it looks useful to learn - and could be excellent for a potential project of mine.

Seen it's usable by non-programmers, but I'm afraid I'm having a tough time figuring what on earth it's all about.
So, maybe a few notes and questions could be useful if anyone is prepared to help me out, sometimes just confirming if my notions correct or wide of the mark. (Who knows, if I figure out a bit of it, may have a go at some info for others who might be even slightly as bamboozled as me. [If there are any such people!])

First, I'm new to Drupal (used Mambo/Joomla); got some notions re Fields, Taxonomy etc.

I have looked at the CCK "Handbook", and much of it went right over my head. Maybe missed easier guide: if so, a link to this should suffice.

Right, so I can create a new content type, save something
But, this isn't interesting.
Need to add Fields, and maybe Groups; and here, I'm sucked into quicksand. (Not Drupal Hell, but an afternoon of befuddlement.)

Groups: just for the heck of it, I created a group - Brian (!) - but was none the wiser about it. What's this a group of? [Fields? - after creating a few, so can cluster together?]

On to Fields; tho really I tried Fields before groups. Various types.
Node reference: On testing, gives content creator chance to select from list of nodes; linked titles of those chosen appear on published page. Could be very nifty.

Integer: so, we're looking at whole number(s) here. Lists; tho not too sure yet what they'd be good for in output.

Decimal: not sure why have Integer and Decimal separate, but presumably works better this way.

Text list: would seem the place if I want to display lists like "spoonbill, swan, egret". But not sure which choice of list is best.
Also choice for leaving blank text box, for content creator to type in.

User reference: Testing, I find that can show my user name, say, link to my profile, in output.

Widget: maybe useful to define what one of these is; I have some idea.

In choosing widget specifications, I also get rather confused. (! - yes, you're expecting that of me by now)

Required/multiple values. I think: must choose a value, and/or can pick more than one value.
Minimum, maximum values for integers. But, what happens to those in between? [Initially, I'd thought that may be automatically generated, rather as Excel can complete cells; but not really so complex]

one value per line, in the format key|label.
so, might have an integer on a line; another integer on next line, etc
labels - might be units of measure

php code ... gonna leave that to the ninjas.

Right, so I can create Fields of several kinds, even if I don't know what they do exactly.
I can assign them to groups, though I don't know what these are groups of (just of fields, for keeping them together?).

I'd guessed that when I edit my cck test content type, I'd see the extra fields. But, no.

I do see the fields when I go to create content, using the cck test type.
Can then do some creation, and have a look at Preview to see results.
These do give some inkling of how to proceed.
One oddity: for the heck of it, I set max integer of 12; but even selecting 1, I'm getting error message saying value can't be over 12.

Right, before I develop further need for boxes of panadols and copious amounts of beer, I'll close now.
Hope the above isn't too taxing.