Unlike other Oracle Cloud services, there are no user roles specific to using Oracle Cloud Stack.
Any cloud user in your identity domain can view and manage stack templates. However, in order to create a cloud stack from a template the user must have the necessary roles to create the specific resources in the stack. For example, in order to create an Oracle Java Cloud Service instance as a resource in a stack, you must have the Java Administrator role.
Only the Identity Domain Administrator is allowed to create user accounts and assign roles. See Managing Users, User Accounts, and Roles in Managing and Monitoring Oracle Cloud.