Learn Portuguese (Portugal): É importante olharem para o maestro antes de entrarem no compasso. - It is important for you to look at the conductor before coming in on the measure.

This is the personal infinitive in action! In English, we say "for you to look". In Portuguese, instead of adding a separate word for "you", we change the infinitive verb itself to show who is doing the action. Adding -em to olhar and entrar makes them olharem and entrarem, which means "for you (plural)" or "for them" to look and enter.

Why do we use the personal infinitive after antes de?

This is exactly what your current lesson covers! When you have a preposition like antes de (before) or depois de (after), Portuguese requires an infinitive verb. If you need to specify exactly who is doing that action (in this case, "you all"), you use the personal infinitive. So, antes de entrarem means "before you (plural) enter".

The translation says "for you to look", but where is the Portuguese word for "you"?

It is hidden in the verb endings. Because olharem and entrarem are conjugated for the vocês (you, plural) or eles/elas (they) form, the speaker does not need to actually say the word vocês. The ending -em gives it away, and the context makes it clear the speaker is addressing the musicians.

Why is it olharem para and not just olharem o maestro?