You can refer to the contents of a package using standard PL/SQL dot notation:
package_name.object_name
package_name.program_unit_name
For example, to call the procedure arrange_windows defined in the package win_manage, you would write the following in a trigger or user-named subprogram:
win_manage.arrange_windows
The same scoping rules apply to packages that apply to user-named subprograms.