Is it just me, or does it sound like там instead of вам, when played at normal speed?
For me, all of the questions on the Russian duolingo sound more or less like a statement.
Is нужно a conjugated form of the verb нуждаться or another verb? I can't find a table/chart that includes нужно.
These are in indeclinable words used in impersonal phrases like this. "нужно" doesn't agree with "Вам" and "молоко" because they both don't do an action. Just remember that "нужно" = "it is necessary" and "нужно было" = "it was necessary"
"можно" is another example: Можно мне взять немного молока? / May I have some milk?