To add another user under your ownCloud account, please follow the steps below.
Go to https://oc1.neural.net.au then login with the username and password provided to you.
Once logged-in, on the upper-right-most part of the screen, you should see your username together with an arrow down icon. Hit the icon, then hit 'Users'.
After hitting 'Users', you'd be directed to the below page. Just type in the Login Name and Password you wish to create for the additional user. Make sure the box under Groups is ticked. (Note that 1660 is a sample group name. Group names are Neural Customer ID or Account Number.) Then hit 'Create'.
After hitting 'Create', the page would then show the user you just added. Under 'Storage', the 'Default" drop down would show you space options you can a give/assign to the user. Just choose whatever space you wish to give just make sure it is not beyond your storage capacity.
You can now give the login credentials to the user and give a go signal to use the ownCloud account!