I will be more clear about the steps:
1. site Administration -> Users -> Permissions -> Define roles
2. click "Administrator"
3. press the "Duplicate role" button
4. when asked "are your sure?" click Yes
5. At the bottom of the next page, you will see a new role called "Administrator copy 1." Click the edit icon (small hand holding pencil)
6. Rename the role "Little Administrator" or something meaningful to you
7. Prevent delete users and delete courses
8. Press save changes
9. site Administration -> Users -> Permissions -> Assign global roles
10. click "Little Administrator"
11. choose a user in right box and use the arrow button to move the user to the left box
Now when the user you assigned in step 11 logs in, he/she should be able to enter any course without being asked to enroll.