You, pretty much, got it.
But your given examples should be:
Mwen gen anpil manje (adj)
I have a lot of food.
Mwen manje anpil.(adv.)
I eat a lot.
manje is a verb and also a noun in Haitian Creole. So this example might be confusing to some students.
______________
As an adjective, anpil is placed before the noun.
Anpil (adj.) → many, a lot of, lots of, several, numerous, abundant, a great deal of
Examples:
Nou gen anpil konfyans nan ou.
We have a great deal of faith in you.
Mwen te ba li anpil lajan.
I gave him lots of money.
Anpil moun te panse li te mouri.
Many people thought he had died.
Gen anpil bagay ou pa'p ka konprann kounye a.
There are a lot of things you can't understand now.
Mwen te rele'l anpil fwa, e li pa't reponn.
I called her many times, and she didn't answer.
As an adverb, anpil modifies a verb or an attribute.
Mwen sonje w anpil. (modifies verb)
I miss you a lot.
Yo te fache anpil. (modifies attribute)
They were very angry.
Nou te mache anpil, anvan nou te rive. (modifies verb)
We walked a great deal before we arrived.
Mwen priye anpil jou sa yo.(modifies verb)
I pray a lot these days.
Li te kontan anpil, lè li te wè w. (modifies attribute)
He was very happy when he saw you.
Mwen te panse anpil sou sa, e repons lan se "non". (modifies verb)
I thought a lot about it, and the answer is "no"
