Unzip the zip file.
Place de Dload folder on the SD, If you want to format the SD first you could do it but it´s no necessary.
Turn off the Cellphone.
Prees Power, Vol+ and Vol- at the same time.
Wait.
Enjoy.
If you want to have a Custom Recovery to install Gapps
1, downloading eng-U8950D_Recovery.rar
2, Unrar eng-U8950D_Recovery.rar
3, click on RE.bat
4, Your phone reboot in CWM
To reboot in CWM
1, turn off the cell Phone
2, Press Power and Vol+
3, Install From SD
4, Select gapps-ics-20120429-signed
5, Ready, Reboot and Enjoy.