Hi & welcome to the forum.
Have you read the help files within Studio? They might give you some idea if you can't follow what I have written below...
I would start by adding a new user to the factory talk security system... This is found down the bottom of the explorer window (window on left hand side) under system --> Users & Groups --> Users.
Right click the Users folder to pop-up a menu where you can select the option of creating a new user.
Next step is to add this user to the runtime security tab. This is again found in the explorer window under System--> Runtime Security. Click this tab & look for an icon to add a user.. This icon is located along the top row of icons - it is the icon on the end which is not greyed out.
Once you have added your user you can click on the close button & save changes.
Are you still with me?
Somewhere in the project you at a minimum will need to add a login button, so your user can logon.
Getting back to your HMI buttons that you have existing, I would right click on them & select the animation-->visibility tab.
You can then write an expression something like systemuser="username" to make the HMI button visible once your user has logged on.
Post back if the above is not clear,, or you need further help