The present tense of the verb "estar" in Spanish is as follows:
• Yo estoy (I am)
• Tú estás (You are)
• Él/Ella/Usted está (He/She/You formal are)
• Nosotros/Nosotras estamos (We are)
• Vosotros/Vosotras estáis (You all are)
• Ellos/Ellas/Ustedes están (They/You all are)
In the given sentence "estamos en la escuela," the correct form of "estar" is "estamos," which corresponds to "we are" in English.