Assuming you want to use the browser to download files, you should navigate to cloud.google.com/console, select the appropriate project and then "Cloud Storage" on the left. That will display a list of buckets to click on, from where the individual objects are available for download.
It's also worth noting, though, that the Cloud Console is really just a convenience; Google Cloud Storage, like other enterprise cloud solutions, is designed around API usage. Google Cloud Storage also offers the gsutil tool that makes the full functionality of these APIs available through a convenient command line interface.