Avd., Pº, Pl. are the kind of street where the house is. - Avd is the short form of "avenida", which means avenue and it's a long street. - Pº is the short form of "paseo", which is a short street. - Pl. is the short form of "plaza" or square. You can also see C/ ("calle" or street) After that you have to write the name of the avenue or the street, in this case Daganzo, Piado or Huertas followed by the number of the building (nº means "número" or number) and the number of the floor. Floors can be written in two form; if in the same floor there are just two houses you difference them by left (izquierda) or right (derecha). If there are more than two, you difference them using letters: A, B, C, D... So if you write "Pl. Huertas nº 15, 21 izquierda" it means Huertas square, building number 15, 21st floor, left door.