When you've created your Skype account, it's not immediately clear how to create another account.
In fact you can create as many new accounts as you like. You can also use the same email address for multiple accounts if you wish.
This can be useful when creating accounts for members of your family, or for a group of employees for example.
Sign out of Skype using File | Sign Out
Now click on the text where it says Don't have a Skype name?
then you will be able to make a new Skype username.