Read the other comments on this page. That will get you started.
For example, right below your post is a comment from hungariandude, in which he says: "The accusative case's main function is to show the direct object of a verb."
If you still have questions, look up "accusative" in an online dictionary. Or take a look at this article from Wikipedia:
Thanks for the reply, but still this is not in layman's terms (nor is the wiki article!) I know sometimes to those who know much on a topic (grammar in this case), it's hard to dumb things down. I think I get it that if there is a verb that refers to a "thing" (in this case, "what" is the thing), then we write "mit". If there is not a verb referring to a "thing" then we just write "mi" as in "what is your name" = "mi a neved". To make sure I'm explaining myself, another example: "what does your name mean?" Here there is a verb referring to the noun "name", so we would use "mit jelent a neved"?
Yes, I think we are hitting the floor with the lingo and to be frank, something like "accusative" would be basic knowledge in most countries' grammar education I know at all...
The thing is, your examples are right but your definition is so loose and vague that I'm not convinced you will be able to distinguish based on this, once there will be other cases.
Most of the time, the accusative marks the "direct object" of the sentence - the thing on which the action is performed or the result of the action. "készít" (create), "lát" (see), néz (watch), szeret (like, love), küld (send), these are all transitive verbs, that is, they can take a "direct object" in the accusative. The last one can also take an indirect object - the target for whom the action happens, the receiver. "Küldtem neked egy sms-t." (I sent you an sms.) Here, sms is in the accusative (and actually, neked is a dative pronoun).
I'm in the same unfortunate boat as you, accusative sounds to me like a sentence where there's an accusation, which I think is wrong.
When I was a kid growing up in Denmark, I was "taught" grammar in school, in danish.
Unfortunately, in the 80's and 90's grammar was taught in a mix between danish and latin terms.
The danish wikipedia article on Akkusativ makes absolutely no sense to someone confused about grammar.
I think your simplified explanation makes this more understandable than anything else I've read.