when do you use a before a name

Question

When do you use a before a name in a sentence? I know you use it before se gusta. when they like somthing, but when else?

Answer 1

When the person is the object of a preposition clarifying the i.o.p.

When the person is the direct object of the sentence.

Le dieron el libro a Juan. (They gave the book to John).

Ella bolfeteó a Juan. (She slapped John.) [personal "a"]

I know you use it before se gusta.

It would be le gusta. (le is an indirect object pronoun. Se is a reflexive pronoun.)

A Juan le gusta acampar. John likes camping.