On the Google Cloud Platform, under the navigation bar, click on Compute Engine and under Storage click on disks.
Then click 'create disk' when the page loads up
Give it a name of your choice eg. 'disk-1', add a description eg. 'External non-boot disk', leave the location in default and don't enable 'regional disk replication' for now.
We are creating a blank disk, we can change the disk settings but we are leaving them in default as well
We can add a snapshot schedule for backup but we are not doing that for this demo and we are leaving google to manage the encryption key for us.
We can add a label but its not important for this demo. The disk we are creating is unformatted and will be when we attach it to a VM. A link on how to format and mount a disk on a VM is provided. Then click 'create'
Wait for a little while and then you'll see it created
You can also check out its details by clicking on it and also do so much more...