Learn Italian: Marco crede al malocchio, ma io non ci credo ancora. - Marco believes in the evil eye, but I still don't believe in it.

In English, we say "believe in". But in Italian, when you believe in a superstition, a fact, or someone's words, you use the verb credere followed by the preposition a. Because malocchio is masculine, the preposition a combines with the article il to make al.

What is the ci doing in non ci credo?

The word ci is a pronoun that replaces a plus a noun or idea. Since the speaker just mentioned al malocchio (a + il malocchio), they use ci to mean "in it" so they don't have to repeat the whole phrase.

Why is the word order non ci credo? Can I say ci non credo?

No, the negative word non must always go at the very beginning of a verb phrase. The pronoun ci acts like it is glued to the verb credo, so they must stay together. Therefore, non goes right before the ci.

Doesn't ancora usually mean "again"?

It can mean "again", but it also means "still" or "yet". When paired with a negative verb, as in non... ancora, it usually translates to "not yet" or "still don't". Here, it means "I still don't believe in it."