[VE][65] totaly lost with <P>, <UL> and nested tables

The main trouble with the validator is that it doesn't show you how its
done in the right way. I'm Dutch and I have to do with the information
given in the Dutch language. I might be wrong, but all those (multiple
documents) help pages about html do say I can nest tables, but its not
allowed in the validator, I can use <P> in the <TD> tag, not in the
validator, I can use <UL> in <TD>, but again not in the validator.
Sorry, I'm totaly lost here. Any good and official information about
html somewhere?

Regards 
Joop