Log in to cp.apwebsites.co.uk
Go to [Web Tools],
Go to [File Manager], you’ll need to enter your account password to proceed.
Go to htdocs, then select [New Directory]
Enter your sub domain name then click [Next Step]
Go to [Domains] in the top menu
Select [Manage] to the right of the domain you want to add to
Scroll down to Sub-Domains & DNS Records and click on [Add]
enter your sub domain name in the first box, and the name of the folder you created in the second box.
You will now need to set an A record within your domain registrar’s control panel pointing at the server ‘A record IP address’ which can be found on the account details tab.
For instructions on how to do this refer to your domain registrar’s help section.