Arriving by metro:
Exit on the Bolhão stop. Turn to Rua Santa Catarina street (main shopping street), turn left, walk up and turn on the first to the right, Rua da Firmeza street, we are at the top left corner (brown/yellow door). 5 minutes walking.
http://www.metrodoporto.pt/

Arriving by train:
1- Exit on S.Bento station turn right to rua 31 de janeiro street, walk up and turn first left, Rua Santa Catarina street. Walk up and turn right on Rua da Firmeza street. 10 minutes walking.

2- Exit on S.Bento enter the metro outside the station, get on the direction Hospital de S.João, exit on Trindade (only 2 stops far from S.bento) and change to the direction Estádio do Dragão, exit on Bolhão station and follow the instructions of arriving by metro.
http://www.cp.pt/

By Bus:
1 - Coming from Spain, catch the bus number 78 next to the bus office, exit on Formosa stop, walk back a few meters until Rua Santa Catarina, turn right and walk up until Firmeza, right again and brown/yellow door. from 15 to 25 minutes.
http://www.internorte.pt/

2 - Rede Expressos station, when you get out the station turn right and cross all the Batalha square until Santa Catarina street, walk up, until the 4th street on the right, Firmeza street a few meters and thats it. 10 minutes walking.
http://www.rede-expressos.pt/

3 - RENEX station, you can rather walk, 20 minutes walking (walking just ask for the direction Santa Catarina and follow any of the other instructions), or catch the same bus nr 78 of the coming from Spain instructions.
http://www.renex.pt/

From the Airport:
Just catch the metro inside the airport 'E' line (purple). 1.35 euros plus 50 cents for the reloadable ticket.
http://www.metrodoporto.pt/