Learn Dutch: Jullie gaan er niet naartoe, het is laat. - You are not going there, it is late.

In Dutch, the combination ernaartoe (meaning "to there") is almost always split in a sentence. The small word er likes to sit early, right after the verb, while naartoe gets pushed to the end of the clause. Other words, like the negative word niet, naturally fall between them.

Could I say Jullie zijn er niet naartoe gaan to match "You are going"?

No, Dutch doesn't use the verb to be (zijn) to make a continuous action like English does with "are going". The simple present tense Jullie gaan translates perfectly to both "You go" and "You are going".

What exactly does naartoe add to er?

By itself, er usually just means "there" as a fixed location. Adding naartoe shows direction or movement toward a place. Because the verb is gaan (to go), you need naartoe to show you are traveling to that destination.

Can I use daar instead of er in this sentence?

Yes, you could say Jullie gaan daar niet naartoe. Using daar puts more emphasis on the specific place, like saying "You are not going TO THAT PLACE." On the other hand, er is unstressed and just casually refers back to a place you were already talking about.