Learn Dutch: Wij hebben een broer en zij hebben een zus. - We have a brother and they have a sister.

In Dutch, all plural subjects (we, you plural, and they) share the exact same verb form in the present tense. For almost all verbs, including hebben (to have), this plural form is simply the whole infinitive (the dictionary form).

The word zij can mean "she" or "they". How do we know it means "they" in this sentence?

You can always tell by looking at the verb next to it! Because the sentence uses the plural verb hebben, we know it means "they have". If it meant "she", the verb would change to the singular form: zij heeft ("she has").

Could I write we instead of wij, and ze instead of zij?

Yes! Wij and zij are the emphasized forms of the pronouns, used when you want to highlight the contrast between what we have and what they have. If you are just stating a casual fact without any special emphasis, you can use the unstressed forms: We hebben een broer en ze hebben een zus.

Does the word en (and) change the word order in the second part of the sentence?