Would this be a reasonable summary?

Nominative - Subject of the sentence

Vocative - Invocation

Accusative - Direct object

Genitive - Possessive (of)

Dative - Indirect object (to, for)

Ablative - Where, when, how (by, with, from)

As long as you realize there are exceptions and addition to all of that, it's a reasonable starting place.

Again, thank you.

These are the only noun cases mentioned & used by the Latin Grammar books i have used, if memory serves me. And yes, the Nominative & Vocative cases are the simplest, while the others are more "nuanced"

The only other one you are likely to run into (unless you are looking at Latin that was archaic in the time of Cicero) is the locative, but that is used only with certain words or in certain circumstances, and the use is not the consistent

Hence I can say "I am in Rome" and that is "Sum Romae" but "I am in Italy" is "Sum in Italia". Cities, house (domus), the country (rus), small islands, etc get the locative but other places just use regular latin. It makes sense, the locative was dropped but stayed around with common words and phrases.

Of course domus is bizarre itself, since it belongs to two different declensions (it stopped being used so much and then made a come back, and was stuck into the 4th declension...so it has 2nd and 4th declension endings)

affirmative to pro ecclesia Dei and apologies to my grammar author (Gavin Betts). From what i can make out, the locative case coincides with the genitive case where proper names of cities, towns, islands using the first & second declension ( used to denote position); to denote motion to or from (the locative coincides with the accusative & ablative sans prepositions); common nouns domus, rus, bellum, militia, humus have temporal meanings with their locative case.