Learn Arabic (Modern Standard): نحن لا نأكل في المتحف.

In Arabic, لا is used to negate present tense verbs, like نأكل (we eat). The word ليس (is not) is used to negate sentences without verbs. Because this sentence describes an action happening right now, we must use لا.

Does لا always go exactly in this spot?

Yes! When negating a present tense verb, لا must come immediately before the verb. You cannot place it before the pronoun. It has to be نحن لا نأكل (we do not eat), never لا نحن نأكل.

Since نأكل already means "we eat", do we actually need to say نحن?

No, you can safely drop نحن and just say لا نأكل في المتحف. The verb نأكل starts with the prefix نـ (n-), which automatically tells us the subject is "we". Keeping نحن at the beginning just adds a bit of emphasis.

Why is there a small symbol over the alif in نأكل?

That is a hamza (ء). It tells you to make a glottal stop, which is a quick catch in your throat like the pause in the middle of "uh-oh." For نأكل (na'kulu), you say "na", make that tiny pause for the hamza, and then say "kulu".