The Botanic Hostel is located in the heart of Zaragoza.
From Delicias Station you can take bus number 34 and it will drop you off at Calle Conde de Aranda and you only have to cross the street and you will be at the hostel!
From the airport you can take the bus and it will drop you off at Paseo Maria Agustin and walk 5 minutes.
You can also take a taxi, from the station it costs about € 8 and from the airport about € 25.