Beginner here. In "Ad familiam nautae pecuniam portabo", is nautae describing familiam or pecuniam? That is, does this translate to "I will carry the money to the sailor's family" or "I will carry the sailor's money to the family"? Or could it be either one?
It is technically ambiguous, and you would chiefly have to rely on context to figure out the answer.
As a general rule of thumb, adjectives do follow the noun, and genitives, acting as a type of modifier, might be more naturally read in this sentence the modifier following familiam than pecuniam, in the same way that if you substituted it for an adjective it would more readily follow familiam.
However, you'll find the genitive preceding its noun very frequently and you'll also find a number of ambiguous sentences throughout Latin literature, so only use it as an initial guide and not a final word.
To clarify the role of nautae, its position would be shifted. Placing it between ad and familiam would force it to pair with familiam, while placing it before portabo would force it to pair with pecuniam. It's still not 100% guaranteed at that point, but it would be the strongest possible case.