Hi Hal,
Lots of good advice already given ... I'll add a comment about an old John-Deere book (now out of print?) called The Operation, Care, and Repair of Farm Machinery.
The tractor-fundamentals section is basic, and the mecanical section outdated-but-useful (I have the 25th ed. - no date given).
Where it offers info I have not seen elsewhere, of use to a new owner, is the section on field-preparation. When to use a plow,harrow, tiller etc., ...what each does... types of , etc.
My JD dealer parts-dept. has no knowledge of a "current" edition. Got mine in the farm/ag section of a used book-store.
Might try the library of an ag.-college, if any are in your locale.
Ordering the ETR book and 2 safety videos today ( thanks, LarryT and MarkC!)
HTH,
Larry