Question

dona magna ab puellis pulchris pueris parvis dabuntur.

Answer 1

@shadow would you mind taking a look at this when you get a chance? off the top of my head, magna means great and puellis means girls but that's all I know

Answer 2

The first thing that jumps out at me is (ab), the ablative preposition, as well as puellis, which is the dative/ablative form of puella, which as Vocaloid said, means girls (plural form).

Going back to the bigger picture though, the first thing you want to do is find the subject and the verb.

Dona is nominative/accusative plural noun (neuter) meaning gifts

Magna is an adjective which means great, as Vocaloid said
It takes on a nominative neuter plural,

So we have:
Great gifts

Next we look at: "pulchris pueris parvis dabuntur."
Pulchris is a dative/ablative adjective taking all genders and plural, meaning beautiful

Pueris is a dative/ablative plural noun of puera and puer, so either boys or girls, depending if it takes a feminine for girl or masculine for boy

Parvis is a dative/ablative plural adjective taking all genders meaning small

dabuntur is our verb, future, passive, indicative, 3rd person, plural of the verb do, which means give.

I recommend this site for verb tenses: http://www.uvm.edu/~bsaylor/latin/cheatsheet.html
Although I ought to just make a post for these on QC lol

So it ought to be translated as: it will be given

Answer 3

Reformatting it for the translation would look like:
Dona magna dabuntur ab puellis pulchris

So,
Great gifts will be given by beautiful girls for small boys.

boys could also be girls, but since it can be both and the adjective for small takes all genders, we can't know for sure.

Dona = nominative
magna = nominative
ab-> puellis pulchris (ablative) - called object of the preposition
pueris = dative
parvis = dative