What is the rule of Indirect Object Pronouns in Spanish like how do you know to put it before a verb or after?

In Spanish, indirect object pronouns typically come before the conjugated verb. However, if the verb is in the infinitive or gerund form, the indirect object pronouns can be attached to the end of the verb. For example, "Le di el regalo" (I gave him the gift) vs. "Voy a darle el regalo" (I am going to give him the gift).