Learn Spanish (Latin America): Vamos a limpiar esos estantes a las dos de la tarde. - We are going to clean those shelves at two in the afternoon.

The word estante (shelf) is masculine, so its plural form is masculine too. To point out masculine plural nouns that are a medium distance away (those), we use esos. If the shelves were right next to you (these shelves), you would use estos.

Why do we need the word a in Vamos a limpiar?

In Spanish, when you want to say you are going to do something, you use a form of the verb ir (like vamos) followed by the word a, and then the action verb in its basic dictionary form (like limpiar). You can never skip the a in this formula!

Why do we say a las dos to mean at two?

To say at a specific hour, Spanish uses a followed by the feminine word for the (la or las). We use las here because dos is plural. If it were one o'clock, it would be a la una.

Why does it say de la tarde instead of en la tarde?