Antes de dormir, les contaré un cuento sobre un cangrejo valiente.

In Spanish, whenever you place a verb right after a preposition (like de), you use the infinitive form. Antes de is a fixed prepositional phrase meaning “before,” so you always say antes de + infinitivo (“before doing something”).

Les is the indirect object pronoun for ellos/ellas/ustedes, meaning “to them.” So les contaré literally means “I will tell to them.” In English we’d simply say “I’ll tell them.”

With a single, conjugated verb in Spanish (like contaré, the simple future), object pronouns go immediately before the verb. You would only attach a pronoun to an infinitive, gerund, or affirmative command. For example:
• Voy a contarles (“I’m going to tell them”) – pronoun attached to the infinitive contar.
• Cuéntales (“Tell them!”) – command form with attached pronoun.

All simple-future endings in Spanish have an accent mark to show where the stress falls and to distinguish them from other tenses. The pattern is:
• hablaré, comeré, escribiré (yo)
• hablarás, comerás, escribirás (tú)
…and so on.

Yes, but there’s a nuance:
• Antes de dormir = “before sleeping” (focus on the action of sleeping).
• Antes de acostarnos = “before going to bed” (focus on the act of lying down/getting ready for bed).
Both are correct – just pick the one that matches what you mean.

In Spanish, most descriptive adjectives follow the noun: un cangrejo valiente (“a brave crab”). Placing valiente before the noun (e.g., un valiente cangrejo) is also possible but gives a more poetic or emphatic feel.

Both prepositions can translate as “about,” but:
• Historias de… is very common with fairy tales or story titles (e.g., cuento de hadas).
• Hablar sobre… or cuento sobre… emphasizes the topic in a more general sense.
In everyday speech, you could hear un cuento de un cangrejo valiente, but sobre makes it clear you’re recounting a story whose subject is the brave crab.