Pharmadex Authority Allocation rules set

How to allow anyone for a particular rules set as authority.
If i want to set a person as screener, using which option I can assign that.

Log in as Admin.
Go to Authorities and Users
From the Authority > Executive>
Select the User from the available list of users.
From the available list of roles on the executor’s roles, select the roles you want to assign to the user.

Now Please help me to know how to add or delete a new Executive’s Roles. Like if I want to add a new role like “Head of vaccine” or “Director” than how to add or remove any. And also “Application type” to add.