To create the Subdomain please follow the below steps:
1: Open the Plesk panel with the credentials you have received on your registered email id.
2: Once you logged in you will see the "ADD SUBDOMAIN" option in your Website&Domain section.

3: Once you click on it you need to choose the subdomain which you want to create for the domain.
4: The directory will setup automatically for uploading your files once you done click on OK.

