Login to the Plesk Control Panel to create additional FTP account.
Click on Websites & Domains tab.
Click on FTP Access link.
Click on Create Additional FTP Account icon.
Assign a user name in FTP account name input box.
Click on marked icon and an additional window will pop up.
In this additional window select a folder to upload FTP file and click OK button to confirm.
Below are the descriptions of above number sequence.
1. Assign a password to access the above FTP user in New FTP password input box.
2. Retype the same password in Confirm FTP password input box.
You are done, your additional FTP account has been created.