If you are using an executable,
- just run the executable (for example: "en_sql_server_2012_express_edition_with_advanced_services_x64.exe")
- Navigate to the "options" tab
- Copy the "Installation Media Root Directory" (should look something like the below snipping)
- Paste it into the open "Browse for SQL server Installation Media" window
Save yourself the hastle of renaming and unzipping etc.!