Follow these steps:
Login to your control panel
Under the FTP Tab (near bottom right section)
Click “FTP Accounts”
Click “Add Account”
For the login field, enter any name you want
Enter a password
The login name will become the created directory. If you entered “joe”, a directory called “joe” will be created under your “www/public_html” directory. If you already have a directory called “joe” then a new directory will not be created.
To login to your FTP account use the following settings in your FTP software.
Users will only have access to the directory you created. If you created a login name called “joe”. Then once logged in, joe can only access the “joe” directory and anything below that, e.g. yourdomain.com/joe/test/. Joe will not be able to access any directory higher than his directory.